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Direct Fired Vapor Absorption Chiller EcoChill Nxt 1 / 2
Direct Fired Vapor Absorption Chiller C o n t e n t s
Company Profile. 3 Working Principle. 13 Design Philosophy. 15 Refrigeration Cycles . 17 Constructional Features and Mechanical Design Considerations . 21 Supply List and Scope of Work . 23 Utility Requirements . 25 Selection Criteria and Procedure . 27 Thermax Nomenclature and the Product Basket . 28 Performance Data . 29 Piping and Instrumentation Diagram . 30 General Arrangement and Foundation Drawing . 32 Instrumentation and Safety Features . 33 Machine Room Layout Considerations . 37 Site Unloading and Installation . 39 Company Profile
hermax is an engineering major providing energy- areas of process heat, captive power and waste heat environment solutions, systems and products in recovery. The company also offers a range of boilers and global markets. The US $ 490 million Thermax is thermal oil heaters, energy efficient chillers and featured in the Forbes List of 'Best Under a Billion' customized products such as waste heat and exhaust Companies in the Asia Pacific. It offers business - to - gas boilers. Thermax's integrated expertise in energy has business solutions to industrial and commercial helped it to offer its customers Combined Heating Power establishments in the areas of heating, cooling, captive and Cooling (CHPC) projects.
power, water treatment, air pollution control, waste management & resource recovery, and chemicals. It Thermax offers industry its expertise over a hundred fuels supports a wide spectrum of industry in over 50 countries - oil, gas and a wide variety of solid fuels including in South East Asia and Japan, Africa and Middle East, biomass. Through diverse installations in several CIS countries, USA, South America and Europe. countries, it has also developed reliable project In the energy business, Thermax executes projects in the management capabilities. EcoChill Nxt 3 / 4
Direct Fired Vapor Absorption Chiller Leveraging its leadership position in electricity saving vapour absorption technology, Thermax offers process industries and commercial establishments like hotels, shopping malls and offices vapor absorption machines a boon in power-starved areas. These eco-friendly, energy efficient equipments have found prestigious customers such as BBC, Mercedes Benz, Audi, Bosch, Panasonic, and Henry Ford Museum.
In the environment area, Thermax offers waste management expertise for solid, liquid and air pollution. Thermax provides solutions from pre-treatment to waste water treatment and chemical conditioning of water for boiler and cooling water systems. Water recycling is a thrust area for Thermax. Hi-grade ion exchange resins from Thermax have found niche customers in the US and Japanese markets.
Thermax has an extensive international marketing network. Headquartered in Pune (Western India), Thermax's 17 international offices are located in South East Asia, Middle East, Africa, Russia, UK and the US. Its overseas subsidiaries - Thermax Europe Ltd (UK) and Thermax Inc (USA) play a significant role in business development. The Thermax group's manufacturing facilities spread over 14 plants, measuring a covered area of over 700,000 sq. ft, are ISO 9001, ISO 14001 and OHSAS 18001 accredited. Thermax manufactures to international standards like ASME, BS, DIN, and GOST. Lloyds, Bureau Veritas, SGS, and TUV have inspected the facilities.
Thermax's business is inspired by the conviction that 'Improving your business is our business.' EcoChill Nxt Chillers and Heaters are available from 100 - 1110 USRT and can achieve chilled water temperature The EcoChill Nxt Series product range represents a culmination of Thermax's global expertise in energy and environment, continuous innovation through focused Research and Development, world-class manufacturing capabilities, efficient and responsive service and a deep commitment to quality and reliability. Testimony to this is provided by over 2500 installations in the last 15 years across 40 countries, appreciation from our customers and several prestigious awards and honors.
Salient features of
n Series flow In series flow cycle, maximum
concentration and maximum temperature do not occur simultaneously in any generator. In other cycles, maximum concentration and maximum temperature occur simultaneously in the High Temperature Generator (HTG). Corrosion rates depend on concentration and temperature. However, when highest concentration and temperature occur simultaneously, corrosion potential increases exponentially. The table below gives approximate efrigeration is a process of extracting heat from a values of concentration and temperature in High low temperature medium and transferring it to a Temperature Generator (HTG) and Low Temperature high temperature heat sink. Refrigeration Generator (LTG) for various cycles.
maintains the temperature of the heat source below that High Temperature of its surroundings while transferring the extracted heat to a heat sink. This operation finds applications in many Concentration Temperature industries ranging from process, engineering, manufacturing, medical, dairy and confectionery, to beverage, hospitality, education and commercial Thus, due to series flow cycle, the corrosion rate is the Absorption chillers, instead of using electricity (high least in Thermax chillers.
grade energy), use heat as energy source which is low n Concentration display and measurement:
grade energy. The energy source may be gas or oil, or Concentration in absorption chiller is analogous to hot water, or it may be waste heat as in exhaust gas from current in electric motor. Motor meets higher load by an engine and steam. Thermax offers a wide range of drawing more current. Similarly, absorption chiller solutions for each of these sources of energy, meets higher load by attaining higher concentration. representing a major advance in Absorption Chilling However, when motor draws current more than it's Technology. EcoChill Nxt Vapour Absorption Chillers rated limits, it may burn. Similarly, in an absorption derive energy from gas (Natural gas, LPG, CNG), light oil chiller, if concentration increases beyond rated value, (HSD, naphtha, SKO) or medium oil (LDO, FO) to provide the chiller crystallizes. Hence, continuously knowing the desired chilling-heating effect. The Direct Fired EcoChill Nxt 5 / 6
Direct Fired Vapor Absorption Chiller the Lithium Bromide concentration is as important as
knowing the current drawn by motor. Thermax has
developed and offers a unique technology to
determine the concentration, which is
continuously displayed on the PLC.
n Crystallization protection: Due to the unique
feature of determining concentration and knowing
temperature of Lithium Bromide coming out from Low
Temperature Heat Exchanger (LTHE), an intelligent
PLC constantly monitors the distance from
crystallization line. If this distance is reduced below
18 F, the PLC proactively takes suitable measures to restore it to 18 F. In other chillers, crystallization prevention measures are taken after inception of crystallization. However, due to advanced technology structural members.
and intelligent panel, Thermax chillers take suitable Long Life: For a capital equipment like Absorption
measures before Lithium Bromide approaches Chiller, life expectancy is 20 years. Thermax Absorption Chillers are carefully designed for long
n Low Cooling Water Supply Temperature
life. For example, for maintaining the required
pump NPSH, height of the chiller is never
Due to sophisticated compromised. If NPSH is not maintained, life of the crystallization protection, Thermax absorption chillers pump will be reduced. After many years of service, can work at rated capacity even with cooling water some parts like heat exchangers, pumps may require supply temperature of 50 F while most of the other repair/replacement. During the repair/replacement, manufacturers require cooling water supply minimum cutting should be required so that exposure temperature of 68 F or above.
of the chiller internals to air will be limited thereby n Multi-fuel capability: The generator design is
arresting corrosion. Hence, all parts are deliberately
such that the chiller can handle gaseous fuels as well kept accessible for increased life of the chiller. If
as liquid fuels.
chiller is made over compact, initially some space advantage can be derived but such advantage will be n In the Direct-fired chiller, furnace is welded to the lost to life reduction later.
chiller frame. When the chiller is started and reaches its capacity, the furnace metal temperature increases. Such increase in temperature is likely to cause expansion in the furnace length. Since structural members restrict the furnace, compressional stresses are developed in the furnace body and in the members supporting the furnace. For lower models, furnace length is small. Therefore, forces restricting expansion are small and hence stresses are low so that they can be easily borne by steel. However, for higher models (frame size 60 and above), even though stresses developed in the furnace body are less than the ultimate tensile stress, over a period of time, parts can buckle under fatigue. To increase reliability and to ensure longer life, furnace of all models with frame size 60 and above, is corrugated type. Corrugated furnace acts like a bellow that neither generates nor passes on the stresses to other NPSH (R) maintained n Thermally efficient cycle: Efficient heat
utilization within the system reduces energy consumption and improves overall system efficiency.
Gravity feed system: Gravity feed of refrigerant
and absorbent enhances heat transfer efficiency and
overcomes the problems of wear and tear and
clogging of nozzles, which use pressurized spraying
techniques.
PLC based control panel, user-friendly interface
and data-logging system ensure easy and smooth
operations. Branded PLC enhances reliability of the Easy access to all parts of the chiller Adjoining pictures (front and rear side of chiller) show Effective corrosion inhibitors: The corrosion
easy access to Low Temperature Heat Exchanger inhibitor minimizes the rate of copper and ferrous (LTHE), Drain Heat Exchanger (DHE), and High metal corrosion on the solution side of the unit. The Temperature Heat Exchanger (HTHE).
corrosion inhibitor used - Lithium Molybdate - is non-toxic and does not generate ammonia, thus protecting the copper tubes in the chiller. Use of Lithium Molybdate is more effective than conventionally used corrosion inhibitors.
n Factory mounted on-line purging system maintains
low vacuum in the shell and ensures consistent performance. Any non-condensable gas, generated inside the chiller during operation, is purged continuously into the storage tank, thus eliminating the need for a replaceable palladium cell. Moreover, as peak concentration and temperature do not occur simultaneously, corrosion rates are low, thereby enabling a small purge tank.
n Rupture disc is provided for protection against
generation of high pressure inside the chiller.
Isolation valves are provided on the pumps,
n Constructional features, such as side exit
facilitating on-line pump maintenance without any loss nozzles, provide ease of maintenance and ensure of vacuum in the system due to the exposure to air.
lower downtime. Hinged absorber and condenser headers provide easy access to the tube bundle, n Double protection, in terms of differential
eliminating the need for heavy lifting arrangements. pressure switch and flow switch, is provided for freeze Crossover piping is factory installed, to avoid work at n Choices for part load operation: User can
n Optional features include VFD control for part
select a chiller with modulating type burner or staged load conditions, standby canned motor pumps, flameproof construction, high pressure headers, EcoChill Nxt 7 / 8
Direct Fired Vapor Absorption Chiller online bearing monitoring, special tube material for Evaporator, Absorber and Condenser, depending on the available water quality, multi-sectional shipment and ‘Factory Performance Test'.
n Service: A global network, powered by over 100
highly trained service personnel, ensures quick response and delivers the right solution to customers. Also on offer are value-added services such as 'e-reach' - remote access for chillers, preventive maintenance contracts, operations and manning and localized customer training programs.
EcoChill Nxt 9 / 10
Direct Fired Vapor Absorption Chiller he boiling point of water is directly proportional to condensation is called the ‘Latent Heat of Condensation'.
pressure. At atmospheric pressure, water boils at For the LiBr - water system, the absorption varies directly 212°F. At a lower pressure, it boils at a lower in proportion with the solution concentration and inversely temperature. At 0.24 inch Hg absolute pressure, the with the solution temperature. Lithium Bromide (LiBr) is a boiling point of water is 39°F.
water soluble chemical, and LiBr - water solution (used To change water from liquid to vapor it has to be heated. as refrigerant) has an inherent property to absorb water The water absorbs the applied heat and its temperature due to its chemical affinity. starts rising, until it reaches the boiling point. At boiling Also, there is a large difference between vapor pressure point, the temperature remains constant but liquid water of LiBr and water. This means that when the LiBr water vaporizes. The heat required to change the phase of a solution is heated, the water will vaporize but the LiBr will liquid to vapor is called the ‘Latent heat of Vaporization'. stay in the solution and become more concentrated.
Similarly the heat rejected by the vapors during Absorption Cycle Overview:
Absorption systems use heat energy to Water (refrigerant) produce a refrigerating effect. In these systems the refrigerant, i.e. water, absorbs Water circulating in the heat at a low temperature and low pressure Heat Exchanger tubes during evaporation and releases heat at a high temperature and high pressure during condensation.
When maintained at high vacuum, water will boil and flash cool itself. LiBr solution, which acts as the absorbent, is Concentrated LiBr solution used to absorb the vaporized refrigerant. The evaporation of the refrigerant takes place at a low pressure.
Vaporized refrigerant Absorption process Concentrated Lthium Bromide solution has affinity towards water.
The solutionAbsorbs vaporized refrigerant water. EcoChill Nxt 11 / 12
Direct Fired Vapor Absorption Chiller The dilute solution, which contains the Refrigerant vapor absorbed refrigerant vapor, is heated at a higher pressure.
Concentrated LiBr solution Water (refrigerant) Driving heat source As Lithium Bromide becomes dilute it loses its capacity to absorb watervapor. It thus needs to be reconcentrated using a heat source. This leads to the vaporization of the Refrigerant Vapor refrigerant and thus the solution is restored Cooling water Condenser to its original concentration. The cycle keeps repeating itself to give the desired chilling refrigerant solution effect. In a double effect absorption the latent heat of condensation, contained in the vaporized refrigerant, is used in a second stage generator to enhance the efficiency of the cycle.
This heat causes the solution to release the absorbed refrigerant invapor form. This vapor is cooled in a separate chamber to becomeliquid refrigerant. The refrigerant goes through a series of Refrigerant vapor processes to complete the refrigerating cycle. These are namely evaporation, absorption, pressurization, vaporization, condensation, throttling and expansion. During this cycle, the refrigerant absorbs heat from a low temperature heat source and releases it to a high temperature sink.
The basic operation cycle of the single effect vapor absorption chiller. Design Philosophy
he design philosophy of Thermax Absorption cooling water temperature.
Chillers is based on three important factors viz. Treliability, energy consumption and ease of Coefficient of Performance (COP): Today,
Thermax chillers offer one of the best COPs. Reliability: While designing absorption chillers, two
Ease of maintenance: This is an important aspect
major problems have to be considered viz. corrosion and of our design philosophy. Even after 5 years of use, crystallization. Since corrosion is caused by temperature, absorption chillers require some small maintenance. So,
concentration and leakages of Lithium Bromide, Thermax if ease of maintenance is ignored in the design has carefully selected Series Flow Cycle (after philosophy, this small maintenance can turn into big
manufacturing Series Flow, Parallel Flow and Reverse maintenance. In addition to the design features listed on Flow Chillers) so that the highest temperature of Lithium pages 5 and 6, illustrated below are some more design Bromide is limited to less than 320 F and maximum features in Thermax chillers that play a role in making concentration is limited to 64 %. A detailed comparison as tabulated on page 5 coupled with the features like n Double sealed valves: All isolating valves and
Crystallization Protection and Concentration service valves have a double seal. More importantly, measurement and display, clearly shows that Thermax the outer seal has no moving parts.
Chillers are reliable compared to the other Chillers.
n Use of branded components: The Thermax
In the series flow cycle, crystallization can occur only in philosophy makes it mandatory to use branded the Low Temperature Heat Exchanger, whereas in other components. Some examples are PLC and Low cycles it can happen in both, the High Temperature Heat Temperature Heat Exchangers. This is because while Exchangers and Low Temperature Heat Exchangers. It Thermax conducts exhaustive reliability tests on self was discovered during the research, that the time taken made components, it still cannot match the years of to de-crystallize High Temperature Heat Exchanger was research and experience put in by internationally 10 times more than that taken to de-crystallize the Low reputed PLC or Plate Heat Exchanger Temperature Heat Exchanger. To eliminate the possibility of crystallization in the Low Temperature Heat Exchanger,
the distance of state point from crystallization curve
is continuously monitored, and if the distance is less
O-RING FOR
than the prescribed value, crystallization control takes MAIN SPINDLE
over and performs suitable actions to prevent The normal method of sensing the high concentration GASKET FOR
EXTERNAL CAP
from generator temperature has a flaw - it fails to work when it is most required. It is a well-known fact that the possibility of crystallization is more when the cooling water temperatures are low. At low cooling water temperatures, the generator pressure lowers and the boiling point curve shifts down. Thus, when the cooling A Double Sealed Valve water temperatures are low, the boiling temperature of Lithium Bromide does not reach the high temperature set n Canned Motor Pump : In Thermax Absorption
point and becomes ineffective protection, even if high Chillers, these pumps are in bolted construction concentration is reached. When cooling water (except for 20 frame, small chillers) so that if required, temperatures are normal, it works well but the possibility bearing and filters can be cleaned after few years of of crystallization is far less. Monitoring the distance from operation. In case of welded pumps, replacement of the crystallization line eliminates such flaws, enabling the entire pump is the only solution.
Thermax to design chillers which can even work at 50 F EcoChill Nxt 13 / 14
Direct Fired Vapor Absorption Chiller Bolted CANNED Motor Pump Welded CANNED Motor Pump What is a Canned Motor Pump?
CANNED motor pump is some times misinterpreted as a pump similar to hermetically sealed compressor of a window air-conditioner. CANNED motor pump is a single unit of a pump and a motor, and has no shaft seal. Shaft seal is a moving joint and cannot pass through stringent helium leak test. In the CANNED motor pump, the pumped liquid is used for cooling motor as well as lubrication of bearings. Hence, the pumped liquid enters the motor section, and in order to keep the liquid away from the motor coil and the rotor, the motor coil and the rotor are sealed with CANS, which are thin metal cylinders. Bolted canned motor pump, bit costly though, offer advantage like replacement of parts, which may be needed after many years of service. Only non-moving parts are bolted and hence they offer excellent leak proof properties while offering maintainability simultaneously.
he Direct Fired Vapor Absorption chiller functions in one of the following modes: Cooling mode, THeating mode or in both modes simultaneously.
Cooling Mode
The Evaporator consists of a tube bundle, an outer shell, distribution trays and a refrigerant pan. A refrigerant pump is used to circulate the refrigerant from the refrigerant pan to the distribution trays. From these trays, the refrigerant falls on to the evaporator tubes. The evaporator shell pressure is maintained at 0.24 inch Hg (a). At this low pressure, the refrigerant evaporates at a low temperature of 39°F (for its evaporation, the refrigerant extracts the required heat from the water which is circulated through the evaporator tubes). As a result, the water in the tubes becomes chilled.
Low Temperature Heat Exchangers The Absorber consists of a tube bundle, an outer shell where it absorbs heat from the condensed refrigerant in (common with the Evaporator) and distribution trays. the Low Temperature Generator. The Low Temperature Generator is housed in the upper The remaining absorbent passes through the Low shell, just above the Absorber. From the Low Temperature Temperature Heat Exchanger, where it absorbs heat from Generator, a concentrated absorbent solution is fed into the concentrated absorbent. the distribution trays, which fall on to the absorber tubes. Both these dilute solutions mix at the inlet of the High On the other hand, the vaporized refrigerant from the Temperature Heat Exchanger. During its flow through the Evaporator is absorbed by the concentrated absorbent, High Temperature Heat Exchanger, this dilute solution leading to its dilution. Due to this absorption, the vacuum absorbs heat from the intermediate absorbent solution. in the shell is maintained at a low pressure, leading to the The solution then enters the High Temperature Generator. desired chilled water temperature. During this process 'Heat of Dilution' is generated. This heat is removed by The Heat Exchangers heat the cool absorbent solution the cooling water circulating through the absorber tubes. before its entry into the High Temperature Generator for As the absorbent solution loses its heat to the cooling regeneration. This reduces the heat input required in the water, it is able to absorb more refrigerant vapor, and High Temperature Generator, thereby increasing the gets further diluted. This diluted absorbent gets collected efficiency of the cycle.
at the bottom of the shell.
High Temperature Generator (HTG)
The High Temperature Generator consists of a furnace, The dilute absorbent is pumped into the High with a shell and tube arrangement on top. Temperature Generator by the absorbent pump. Heat is supplied to the HTG by fuel combustion. As a A part of it first passes through the Drain Heat Exchanger, result, hot flue gases pass through the HTG tubes and EcoChill Nxt 15 / 16
Direct Fired Vapor Absorption Chiller the dilute absorbent surrounding these tubes gets heated. The temperature of the solution keeps on increasing till it reaches its boiling point and the absorbed refrigerant boils out of the solution. The solution concentration increases and it (the increased concentration) is referred to as the intermediate concentration. The vaporized refrigerant generated passes through the Eliminators and goes to the tube side of the Low Temperature Generator.
Low Temperature Generator (LTG) and
Condenser
The Low Temperature Generator and condenser tube Side-by-side Evaporator and Absorber bundle are enclosed in the upper shell with an insulation High Temperature Generator pass directly to the plate separating the two. The vaporized refrigerant flows Evaporator through the changeover valve and condense into the LTG tubes. It heats the intermediate absorbent on the outside of the evaporator tubes. In turn, the water outside and in the process gets condensed. This flowing inside the evaporator tubes gets heated. The condensed refrigerant flows to the Condenser through condensed refrigerant gets collected at the Evaporator the Drain Heat Exchanger. bottom and eventually overflows into the Absorber. To On the other hand, the refrigerant, vaporized in the Low enable overflowing, the refrigerant pump is kept switched Temperature Generator, passes through the Eliminators to the Condenser. Cooling water circulates inside the condenser tubes. The refrigerant vapor condenses on the outside of the condenser tubes and collects at the Concentrated absorbent solution, from the High bottom of the Condenser. Temperature Generator flows into the Absorber through Finally, the condensed refrigerant from the LTG and the another changeover valve, kept open in the heating condenser mix, and flow into the Evaporator. The mode. This concentrated absorbent mixes with the absorbent, now concentrated in the LTG, flows to the overflowing refrigerant from the Evaporator and gets Absorber to begin a new absorbent cycle.
High Temperature Generator (HTG)
The High Temperature Generator consists of a furnace, with a shell & tube arrangement on the top of it. Heat is supplied to the HTG by combustion of fuel. The hot flue gases pass through the HTG tubes. The dilute absorbent surrounding these tubes gets heated. The temperature of the solution increases until it reaches its boiling point. The absorbed refrigerant boils out of the solution. The solution concentration increases. This concentrated absorbent flows into the Absorber. The vaporized refrigerant passes through the Eliminators and goes to the Evaporator. The LTG and the Condenser In heating mode, the refrigerant vapors from the High Heating Mode
Temperature Generator flow directly to the Evaporator through the changeover valve.
Cooling water does not flow through the Absorber and In heating mode, the hot water flows inside the the Condenser, during this mode.
evaporator tubes. Also, the refrigerant vapors from the EcoChill Nxt 17 / 18
Direct Fired Vapor Absorption Chiller Constructional Features And
Mechanical Design Considerations
coChill Nxt chiller can be designed to conform to 114 psi (g). Gravity feed spraying technology is applied the codes and standards given below. Whenever to spray the solution in the Absorber and Evaporator. The no specific standard is applicable, the design is solution in the spraying tubes sprays downward to according to good and proven engineering standards.
ensure good film thickness and better heat transfer. The n ISO 9001:2000 n ISO 14001 n ETL n CE n PED Absorber and Evaporator are separated by an Eliminator n TUV n DNV n ASME n OHSAS 18001 that prevents the carryover of LiBr from Absorber to Evaporator, while allowing the water vapor from Evaporator to cross over to the Absorber. The lower shell is mounted on the base frame. The upper shell houses a Low Temperature Generator and a Condenser. This shell is also fabricated from carbon steel plates. Smooth copper tubes are used in the Condenser and finned carbon steel tubes in the Low Temperature Generator. An Eliminator separates the Low Temperature Generator and Condenser. This Eliminator prevents the carryover of LiBr from the Low Temperature Generator to the Condenser. The upper shell rests on the lower shell. A rupture disk is provided for protection against high pressure. The High Temperature Generator is a shell and Tube Heat Exchanger with carbon steel tubes located on top of a furnace. The shell is fabricated from carbon steel. Hot gases, generated through oil/ gas combustion, provide heat to the absorbent and are vented through the exhaust gas duct.
The Burner is of forced draft type with cast aluminum housing. If required, it is capable of operating on both liquid and gaseous fuels. For ease of service, the burner swings open laterally. In addition, a removable cover allows access to the serviceable components. It The lower shell with a sight glass incorporates a self-regulating differential combustion air The lower shell houses two shell and tube heat pressure switch and a burner flange safety interlock exchangers: the Absorber and Evaporator. This shell is switch. A sight glass is provided to enable flame viewing. fabricated from formed carbon steel plates with fusion The combustion air fan is statically and dynamically welded seams. Carbon steel tube sheets are drilled and balanced. Air intake consists of multiple aluminum vanes reamed to accommodate absorber and evaporator on the suction side for combustion air regulation. This tubes, and the tube ends are expanded to ensure no combustion air can also be adjusted to suit the firing rate. leakages between the shell and tube side. The support The combustion head consists of stainless steel alloy plates inside the shell are also fabricated from carbon flame tubes and a stainless steel alloy diffuser assembly. steel plates. Enhanced copper tubes are used in the Whenever required, the fuel changeover is simple and Absorber and Evaporator. Maximum working pressure is does not re-adjustments. The 3-phase TEFC blower EcoChill Nxt 19 / 20
Direct Fired Vapor Absorption Chiller Marine type headers motor is fully compatible for use with a variable frequency drive.
By utilizing the heat within the system, the Regenerative Heat Exchangers increase the efficiency of the cycle. Marine type water boxes are provided with the Absorber and Condenser. These boxes enable easy tube cleaning and replacement. The drain and vent connections attached to these boxes are of great help while removing the cooling water hold-up when the chiller has not been in use for a long time. The absorbent and refrigerant pumps are canned motor type and are factory mounted. The motor is directly coupled with the pump. Isolation valves are welded at the inlet and outlet, enabling easy maintenance of pumps without loss of vacuum. All valves, for adjusting solution, are fully welded to prevent leakage of air into the unit.
Non-condensable gases are removed from the chiller chiller by operating the vacuum pump and by opening the manual purge valves. Service valves are provided for N2 charging, for sampling, and for connecting the Manometer.
Purge System Supply List And Scope Of Work
Common Shell and Tube sheets, separate water boxes Low Temperature Generator Common Shell and Tube sheets, separate water boxes High Temperature Generator High Temperature Generator with with Burner Assembly combustion chamber and burner Low Temperature Heat Exchanger Plate Heat Exchanger High Temperature Heat Exchanger Plate Heat Exchanger Drain Heat Exchanger Plate Heat Exchanger Absorbent Pump and Motor Canned Motor Pump Set Refrigerant Pump and Motor Canned Motor Pump Set Purge Pump and Motor For Separation of Non-condensable gases from absorbent and its storage.
Inter-connecting Piping Control Panel, Field Instruments, Cabling. Starters, Circuit breakers, Wiring within battery limits.
Operation and Maintenance Manual, Packing List.
EcoChill Nxt 21 / 22
Direct Fired Vapor Absorption Chiller Distribution of Scope of Work -Manufacturing, Transportation and Installation Chiller Manufacture with accessories Refer to Supply List.
Supplied by Thermax specified Thermax Optional Feature.
On-site Erection Supervision of Commissioning Customer to assist, Thermax Representative will supervise the commissioning.
Loading at Thermax Factory Port in India to port of destination* Unloading at Job-site Storage at Job-site If required.
Construction and Installation Handling at Job-site Rigging, Shifting to actual Piping outside battery limits Refer to Supply List.
Butterfly valve in the cooling water line If required. (Refer to Safety Functions under Instrumentation and Safety Features.) Chiller insulation* Piping insulation outside battery limits Refer to Supply List.
Electrical connections outside Refer to Supply List.
Assembly and on-site connections For (a) Burner and (b) Multi- Sectional Shipment (Optional).
Operation and Maintenance Training of Customers' Operators during commissioning (maximum period of 7 days) NOTE: * indicates that the scope of supply can also be included by Thermax, as an option.
Chilled/ Hot Water: The chiller's design ensures in
As the cooling water circuit is open, the salts get delivering the desired cooling capacity. The chilled water concentrated due to evaporation taking place in the flow rate to the chiller is kept constant. Hence its capacity cooling tower. This can be adjusted by controlling cooling is proportional to the difference in the temperatures of the water blow-down and make-up. Moreover, exposure to inlet and the outlet chilled water.
sunlight favors biological growth. Slime is more detrimental to heat transfer than scale. Dosing biocides Cooling Water: Cooling water is used to remove
during cooling water treatment can minimize these heat of absorption and condensation. The chiller can be adverse effects.
designed to suit the rated cooling water temperature of Unlike the cooling water circuit, which is always open, the chilled water circuit may be open or closed. Due to the Energy Source: The chiller is designed for fuel
lower temperature, chilled water circulating in an open flexibility. The liquid and gaseous fuels that can be used circuit does not have severe consequences. Soft water is are Light Oil, SKO (Superior Kerosene Oil), Natural Gas, recommended for use in this circuit.
CNG and other gaseous fuels.
Air: Compressed air is required for the pneumatic
operation of the control valve. The supplied air should be
moisture free and the required pressure is 100 psi(g).
Electricity: The power supply to the chiller shall be
strictly as per the voltage and frequency rating given on
chiller nameplate.
To avoid scaling and corrosion, we recommend maintaining water quality as given in the instructions. If the water quality at the installation site is different, the chiller can be designed to adjust to it.
Chilled Water and Cooling Water
Treatment
Water treatment of the chilled and cooling water is important to get desired chiller performance and for its long life. If the water quality is bad, it shows scaling and/or corrosion tendency. As a result, sludge and scale can adhere to the inside of the tubes. This impedes heat transfer between the chilled water and refrigerant and between the cooling water and LiBr solution. Consequently, there can be an increase in the respective temperatures of the LiBr solution and the condensed refrigerant, leading to an increase in the fuel consumption and thus hampering the capacity and efficiency of the . In cases of prolonged corrosion, the tubes will chillerrequire maintenance or, in some cases, they may even have to be replaced. EcoChill Nxt 23 / 24
Direct Fired Vapor Absorption Chiller JIS recommends the following water quality for copper tubes: Electrical Conductivity (max.) M Alkalinity (max.) Total hardness (max.) Chloride ion (max.) Sulphate ion (max.) Total Iron (max.) mg S/lit Not detected Ammonium ion (max.) Silica ion (max.) Free carbonic acid (max.) Electrical Conductivity (max.) M Alkalinity (max.) Total hardness (max.) Chloride ion (max.) Sulphate ion (max.) Total Iron (max.) mg S/lit Not detected Ammonium ion (max.) Silica ion (max.) Suspended solids (max.) Selection Criteria And Procedure
The following factors govern model selection: Absorption is a complex phenomenon involving heat and mass transfer. The chiller consists of multiple interlinked Energy Source Parameters: Energy source can
heat exchangers. In such a complex mechanism, be either natural gas or light oil (containing less than 1% deration factors and two-dimensional graphs can lead sulfur). Required gas pressure is 65 mbar. Both only to approximation. At Thermax, every selection is modulating and Hi-Low burners are available for the done with the help of a computer program that does machines; 3-stage burners can also be offered as an option. Fuel consumption given is based on standard detailed heat and mass transfer calculations for each natural gas and oil HHV. However, for different gas / oil, heat exchanger and accurately determines performance fuel consumption will be proportional to the ratio of LHV.
of the chiller. When using media other than water or for non-standard fouling factors, the selection considers Chilled and cooling water temperature:
appropriate properties to evaluate overall heat transfer Capacity of the chiller varies based on chilled water outlet coefficient. The program facilitates optimization of the temperature and cooling water inlet temperature. The energy / fuel consumption, the chilled and the cooling chiller is capable of delivering higher than its rated water flow rates and the pressure drops.
capacity if chilled water temperature is higher than the rated temperature or cooling water temperature is lower The following document provides performance data and than the rated temperature. Conversely, the chiller the dimensional data for all the standard models.
capacity is likely to be reduced if chilled water temperature is lower and cooling water temperature is higher than their respective rated temperatures. Thermax has designed and installed chillers for chilled water temperatures ranging from 38 F to 70 F and cooling water temperatures varying from 50 F to 97 F.
Chilled and cooling water circuit pressure:
Thermax's standard product range is designed for a
maximum pressure of 114 psi (g) in the chilled and
cooling water circuits. Thermax also offers special design
for higher pressures.
Size: If there are constraints relating to the
transportation of the chiller or machine room access,
Thermax offers the option of multi-sectional shipment.
Typically, this can be in three sections viz. lower shell,
upper shell and High Temperature Generator. These
sections can be assembled at the installation site by just
welding a few connections.
Optional features: These include tube material of
construction, frequency drive for double effect absorbent
pumps, flame proof construction, claded tube sheets and
special electronics and instrumentation.
EcoChill Nxt 25 / 26
Direct Fired Vapor Absorption Chiller Thermax Nomenclature And
The EcoChill Nxt Product Basket
Efficiency: Extra Efficient Machine type: Chiller Machine size within the Frame Cycle: Double Effect Primary heat Source: Gas Efficiency: Extra Efficient Machine type: Chiller Machine size within the Frame Cycle: Double effect Primary heat Source: Oil o. of passes (Evaporator) o. of passes (absorber) o. of passes (condensor) Total Electric Input learance for Tube R EcoChill Nxt 27 / 28
Direct Fired Vapor Absorption Chiller Typical P & I Diagrams
Light Oil Fired
OIL FROM STORAGE TANK CHILLED/ HEATING WATER OUTLET CHILLED/ HEATING WATER INLET VAPOR ABSORPTION CHILLER HEATER COOLING WATER PUMPS (1 WORKING + 1 STD BY) GATE VALVE (OPEN) GATE VALVE (CLOSE) FAST ACTING VALVE GLOBE VALVE (OPEN) GLOBE VALVE (CLOSE) MONO BLOCK BURNER THREE WAY CONTROL VALVE BUTTERFLY VALVE (OPEN) AIR FILTER REGULATOR BUTTERFLY VALVE (CLOSE) "Y" STRAINER T - TEMPERATURE C - CONTROLLER L - LOW FOR REFERENCE ONLY Gas Fired
CHILLED/ HEATING WATER OUTLET CHILLED/ HEATING WATER INLET VAPOR ABSORPTION CHILLER HEATER COOLING WATER PUMPS (1 WORKING + 1 STD BY) GATE VALVE (OPEN) GATE VALVE (CLOSE) FAST ACTING VALVE GLOBE VALVE (OPEN) GLOBE VALVE (CLOSE) MONO BLOCK BURNER THREE WAY CONTROL VALVE BUTTERFLY VALVE (OPEN) AIR FILTER REGULATOR BUTTERFLY VALVE (CLOSE) "Y" STRAINER T - TEMPERATURE C - CONTROLLER L - LOW FOR REFERENCE ONLY EcoChill Nxt 29 / 30
Direct Fired Vapor Absorption Chiller General Arrangement Drawing
Typical General Arrangement Drawing
NOTES1) INDICATES THE POSITION OF ANCHOR BOLTS2) INDICATES THE POSITION OF THE POWER SUPPLY CONNECTION ON THE CONTROL PANEL 3) MINE INSTALLATION CLEARANCE (Min-inches) 4) CONTROL PANEL SIDE : 47.5"5) TOP: 8"6) OTHERS: 20" For reference only Typical Foundation Drawing
ARRANGEMENT AT ANCHOR Notes1. There should be a drain ditch around the foundation.
2. The floor surface should be made as water proof for ease of maintenance work.
3. Finish the foundation work horizontal y flat & smooth at the horizontal grade of about 1/1000.
4. The foundation shal be designed to suit the soil conditions & other design considerations at site.
Instrumentation And Safety Features
The control panel includes the following
components:
! Programmable Logic Controller (PLC) ! Panel view operator interface ! Power circuit for pumps ! Panel mounted instruments The total heat extracted from the chilled water defines the cooling capacity of a chiller. The chilled water inlet flow-rate is kept constant. Hence the cooling capacity is proportional to the difference in the temperatures of the chilled water at inlet and outlet.
Load changes are reflected in the rise or fall of the temperature of the inlet chilled water. The outlet chilled water temperature varies with the inlet chilled water temperature. An RTD sensor notes this change in temperature. This temperature signal is fed to the PLC.
signal into a firing control signal, which controls the An inbuilt software PID control loop processes this signal position of the burner modulation. As the load increases, with respect to the chilled water set point. A control the burner firing also increases, and vice-versa, thus output signal of 4 to 20 mA is sent to the burner for regulates the quantity of fuel entering the burner.
In High - Low type of burner, an RTD sensor in the chilled The burner controller converts the 4 to 20 mA electrical water outlet notes the change in temperature. This signal is fed to the PLC which then sends it to the burner control panel as Control output (Digital Signal, Potential free) in terms of either HI or LOW. This signal controls the output of the burner. As the temperature of the chilled water outlet drops below the set point value, the burner is fired in Low flame and if it continues to drop and reaches set point minus preset value, the Burner is switched OFF. Depending on the load conditions, the chilled water temperature at the outlet starts rising, and as it crosses the control range, (set value in the PLC), the burner is switched ON, to control the temperature. EcoChill Nxt 31 / 32
Direct Fired Vapor Absorption Chiller stop the chiller like: l H-cut (for heating mode): Sometimes the load may fall
Safety devices are provided to protect the chiller from sharply, due to which hot water temperature starts reaching abnormal conditions, to safeguard it from rising. When the hot water temperature rises above hot damage, and to ensure continued availability.
water out set point plus H cut differential set point, the Safety devices are:
burner is switched off. The H - Cut is set from the Heat - Chiller mounted safeties, located on the chiller mode control loop screen. This safety prevents further - Panel mounted safeties, in the control panel, and temperature rise in hot water. The burner will start firing - Field interlocks passing signals from the field to the at minimum firing after hot water outlet temperature goes below the hot water out temperature plus H - Cut differential minus the hysteresis.
l Chilled/ hot water flow switch l L-cut: If the chilled water outlet temperature drops
Paddle type device mounted on the chilled water outlet below the L-cut set point, the refrigerant pump is switched off, stopping the burner immediately. This l Chilled/ hot water Differential Pressure (DP) switch safety prevents any further temperature drop in the Connected to the inlet and outlet chilled water nozzles chilled water. As the chilled water outlet temperature l Refrigerant level electrodes rises above the L-cut set point plus the hysterisis set Mounted in the refrigerant level box point, the refrigerant pump restarts, which in turn l Generator level electrodes restarts the burner, depending on the PID controller.
Mounted in the high temperature generator level box l Antifreeze: If the chilled water outlet temperature
l Absorber level electrodes drops below the internal antifreeze set point, the chiller Mounted in the absorbent level box trips and the 'TOTAL SHUTDOWN' alarm sequence is l Auto blow down solenoid valve carried out. The alarm should be reset only after the Mounted on refrigerant pump outlet tapping to chilled water outlet temperature rises above the internal antifreeze set point plus the hysterisis set point.
l Temperature sensors mounted at various locations to l Chilled/ hot water pump interlock: Chilled water
l Furnace temperature sensor.
flow is a prerequisite for chiller operation. A potential l Generator Pressure switch.
free contact is to be wired from the chilled water pump l Furnace pressure switch.
motor starter to the chiller panel to sense chilled water pump ON/ OFF/ TRIP status. The chiller starts only when the chilled water pump is ON. If the chilled water l Generator level controller pump stops/ trips during operation, the 'TOTAL l Refrigerant level controller SHUTDOWN' alarm sequence is carried out.
l Absorbent level controller l Absorbent pump overload relay / AC Drive l Cooling water pump interlock: Cooling water flow
l Refrigerant pump overload relay should be stopped immediately when the chilled water l Purge pump overload relay flow stops in the chiller. So the cooling water pump should be started through the start permissive of cooling water pump.
l Cooling tower start/ stop permissive contacts l Cooling water pump/ shut off valve - permissive l Chilled/ hot water flow switch: If the chilled water
l Chilled/ hot water pump - permissive.
flow drops below 50% of the rated value, the chiller trips and the 'TOTAL SHUTDOWN' alarm sequence is carried out.
l Chilled/ hot water differential pressure switch: If
The safety functions of the chiller protect it against the differential pressure across the chilled water inlet abnormal conditions. The various safety functions and outlet lines drops below the rated value, the chiller Antifreeze protection: To prevent the chilled water
trips and the 'TOTAL SHUTDOWN' alarm sequence is carried out.
from freezing in the evaporator tubes, the safety functions l Generator pressure switch: If the generator
dilution cycle immediately. The HTG high temperature pressure increases above 29.9 inch Hg, chiller trips alarm cannot be reset until the HTG temperature drops and 'DILUTION CYCLE' alarm sequence is carried below the set point minus the hysterisis set value of l Butterfly control valve in cooling water line: If all
l HTG high pressure safety: If the HTG pressure
the cooling water pumps can be stopped electrically exceeds the HTG pressure switch setting, the when the differential pressure switch or flow switch 'DILUTION CYCLE' alarm sequence is carried out and shows less or no flow in chilled water, automatically the chiller goes into the dilution cycle immediately. The operated butterfly valve is not required. However, HTG high-pressure alarm cannot be reset until the HTG when such arrangement can not be ensured, auto pressure drops below the HTG pressure switch setting.
butterfly valve needs to be provided by the customer l Stack high temperature safety: If the stack
to stop the cooling water based on differential temperature exceeds the stack high temperature set pressure switch / flow switch signal.
point of 482°F, the 'DILUTION CYCLE' alarm sequence l Crystallization prevention: If the concentrated
is carried out and the chiller goes into the dilution cycle absorbent solution, while returning to the Absorber immediately. Stack high temperature alarm cannot be from the Low Temperature Generator is excessively reset until the stack temperature drops below the set cooled, it crystallizes in the Low Temperature Heat point minus the hysterisis set value 9°F.
Exchanger, affecting the chiller operation. l Cooling water low temperature safety: If the
Crystallization occurs, either, when the concentration cooling water inlet temperature drops below the of the absorbent (related to its temperature) cooling water low temperature set point, the 'DILUTION becomes too high or its temperature drops CYCLE' alarm sequence is carried out. The chiller goes excessively. The following safety functions prevent into the dilution cycle immediately. The alarm cannot the chiller from crystallizing: be reset until the cooling water inlet temperature rises l Burner modulation on crystallization prevention
above the cooling water low temperature set point plus safety: The strong solution concentration and the
hysterisis set value.
crystallization temperature corresponding to that l HTG Vapor saturation temperature high: If the HTG
concentration are calculated in the PLC. The PLC vapor saturation temperature exceeds the high HTG always tries to maintain the pre-set safe distance vapor temperature set point, the 'DILUTION CYCLE' between the crystallization temperature and strong alarm sequence is carried out and the chiller goes into solution temperature of low temperature heat the Dilution Cycle immediately. The alarm cannot be exchanger outlet. If the distance is less than the pre- reset until the HTG vapor temperature goes below the set safe distance, the PLC switches on/ off or HTG vapor temperature trip set point minus the set modulates the burner so that the strong solution will hysterisis value.
never reach crystallization zone.
l Furnace pressure switch: If the furnace pressure
l Absorber level safety: Minor crystallization in the
exceeds the set point, the 'DILUTION CYCLE' alarm chiller can result in low absorber level. When the sequence is carried out and the chiller goes in to absorber level falls below 25% of the sight glass, the Dilution cycle. The alarm can only be reset when the blow-down solenoid valve opens. It closes when the when the furnace pressure goes bellow the furnace absorber level goes above the 50% level of the sight pressure switch set point minus the set hysteresis glass. The opening of the blow-down solenoid valve allows the flow of refrigerant from refrigerant pump to absorber. Burner modulation opens only when the l Furnace outlet temperature high: If the furnace
absorber level reaches the 50% level of the sight outlet temperature exceeds the furnace temperature glass. Adequate level ensures dilute solution supply set point, the 'DILUTION CYCLE' alarm sequence is to generator thus preventing crystallization.
carried out and the chiller goes in to Dilution cycle. The alarm can only be reset only when the furnace l HTG high temperature safety: If the HTG
temperature goes bellow the Furnace Temperature Trip temperature exceeds the HTG high temperature set set point minus the hysterisis value.
point of 320°F, the 'DILUTION CYCLE' alarm sequence is carried out. The chiller goes into the EcoChill Nxt 33 / 34
Direct Fired Vapor Absorption Chiller Cavitation protection of refrigerant pump:
Burner trip: If the burner trips frequently just before
The refrigerant pump starts to cavitate, when the firing, then there is a possibility of fuel leakage into the refrigerant level in the evaporator pan falls below the set furnace without getting burnt. The leaked fuel will get level. To ensure minimum acceptable suction pressure, collected at the bottom of the furnace and it can get the refrigerant level is not allowed to fall below a certain instantaneously burnt (causing an explosion) when the level by means of three level electrodes and a level relay.
burner fires subsequently. This has to be prevented by all means. The following safety function prevents this The three electrodes are mounted in the refrigerant level box assembly present on the lower shell. The pump If the burner trips for more than 3 times within the pre-set starts when the level reaches the electrode that is period in the PLC, say within 10 minutes, then the chiller smallest in length. It stops when the level goes below the invariably goes into 'DILUTION CYCLE' alarm sequence longest electrode. When the level goes below the with an alarm 'check for fuel leakage in the furnace'. Until intermediate electrode, a delay of 20 seconds is provided the alarm is reset, the chiller cannot be re-started. before the pump can be switches off automatically.
Cavitation protection of the absorbent
pump: The absorbent pump starts to cavitate when the
absorbent level in the absorber sump falls excessively. To
prevent the excess absorbent from being pumped out of
the absorber sump, the absorbent level in the HTG is not
allowed to rise above a certain level. This is done by
means of three level electrodes, and a level relay.
The three electrodes are mounted on the high temperature generator level box. The absorbent level is to be maintained below the smallest electrode. The longest electrode acts as the reference electrode. When the level reaches the smallest electrode, the pump stops after a delay of 5 seconds. The pump restarts when the level goes below the intermediate electrode.
l Absorbent pump overload relay: If the absorbent- pump motor draws more than its rated current, the overload relay trips. The 'TOTAL SHUTDOWN' alarm sequence is carried out. The alarm cannot be reset until the absorbent pump overload relay (inside the control panel) is manually reset.
l Refrigerant pump overload relay: If the refrigerant pump motor draws more than its rated current, the overload relay trips and the 'DILUTION CYCLE' alarm sequence is carried out. The alarm cannot be reset until the refrigerant pump overload relay (inside the control panel) is reset manually.
l Purge pump overload relay: If the purge pump motor draws more than its rated current, the overload relay trips. The alarm cannot be reset until the purge pump overload relay (inside the control panel) is reset manually.
Machine Room Layout Considerations
Location: Unlike conventional electric chillers,
vent, drain and sampling connections. It should have absorption chillers are characterized by their silent minimum pressure drop and should be tested for operation and simpler foundation. Owing to this, they can be located in basements or on terraces of buildings; the l In the connecting lines, the field instruments should be location being ultimately decided by space availability installed adjacent to the chiller. Design and routing of and ease of installation and maintenance.
the piping should provide easy access to the field Room Size:
instruments for effective maintenance.
The machine room size should be decided according to the dimensions of the chiller. A l The crossover piping from the absorber to the provision of minimum 3.3 ft clearance space should be condenser is a standard feature of Thermax absorption made on all sides of the chiller. In addition, provision for tube removal space should be made on either side of the chiller. A clearance of 3.95 ft is recommended on the l The piping should be adequately supported to prevent panel side of the chiller and 0.7 ft is recommended on any strain on the chiller nozzles and connecting the top of the chiller. For more details please refer to the Dimensional Data given in this document. l Check whether the air-vent valves, drain valves and the pressure gauges are provided on the chilled water, Ambient Temperature: Temperature in the machine
cooling water, fuel and drain piping. The drain room should be in the range of 4 F to 113 F.
connections should be at the lowest point, whereas the air-vents should be at the highest point on the piping. The humidity inside the chiller room should be less than 85%. High humidity can result in corrosion l The inlet chilled water line, hot water line and the inlet and failure of electrical equipment. The chiller room cooling water line to the chiller should be flushed should be adequately ventilated. clean, before connecting these to the chiller.
Drainage: All the discharge pipes and overflow pipes
l Check the connective direction of the chilled water and should be routed to the drains. The drains should be the cooling water piping.
covered. The slope of the drainage system should be l Check the valve positions on the chilled water piping, such that there is no accumulation of water. In case the cooling water piping, fuel and drain piping.
chiller room is built in the basement, a water tank and pump is required for proper drainage.
l Make sure that strainers are provided in the water l If cooling water pump is not dedicated to individual Fuel (oil/ gas) piping should be designed and installed to chiller, auto-operated butterfly valve is necessary in the meet the prescribed safety standards. Pipe sizing should cooling water circuit.
be as per the required flow rates.
l For oil-fired systems, the fuel tank should be equipped with safety devices such as firetrap, level controls and l All field wiring should be in accordance with applicable vent, drain connections. The fuel tank should not be exposed to rain. Filters should be installed at the inlet l Use Copper conductors only.
and outlet of the fuel tank. Depending on the elevation of the fuel tank with respect to the burner, a day tank l All wiring should be checked regularly for any damage may be required.
and all terminal connections tested for tightness.
l For gas-fired systems, the piping design pressure l The power supply specifications should match those should be higher than the working pressure. The piping on the unit nameplate. Voltage must be within 15% of should be equipped with a stop valve, safety devices, nameplate value.
EcoChill Nxt 35 / 36
Direct Fired Vapor Absorption Chiller l For minimum circuit ampacity and maximum fuse size, l The machine room should have adequate ventilation see the unit nameplate.
for sufficient burner make-up air and for effective flue gas removal. The machine room pressure should never l Wiring to the chiller control panel should be proper.
fall below the flue gas outlet pressure. The chimney l Proper wiring should be provided from the chiller location should depend on the atmospheric conditions control panel to the control valve.
and the position of the cooling tower and vents.
l Proper interlocking of chilled water and cooling water l Soot should be removed from the system. Heat with the chiller control panel should be provided.
resistant material should be used for its construction. Ducts should be properly insulated. The chimney should have lightning arresters with proper earthing connections. It should have effective protection from l Use adhesive agents, iron wires and bounds to mount rain, wind and snow. Expansion joints should be insulation material. These should not be fixed/ provided to limit thermal stresses.
mounted using tapping screws or rivets.
l Use non-combustible insulation material. This could be wool or polystyrene foam in case of cold surfaces, and glass wool in case of hot surfaces.
l The insulation should not cover the cap of the damper, sight glass, handle of the refrigerant lowdown valve, refrigerant pump motor, refrigerant level electrode box cover, HTG level electrode level box cover and the service valves.
l For effective in-tube cleaning, the evaporator header should be removable.
l To assist in-tube inspection, the HTG headers should be removable.
l In addition to this, following components should also have removable insulation: Ø Chilled water flow switch Ø Chilled water freeze protection thermostat Ø Chilled water temperature sensor Flue Gas Duct Guidelines
l The flue gas duct and chimney should be designed and installed to comply with prescribed specification and safety standards.
l The flue gas duct and chimney should be designed so that the outlet pressure is slightly negative. The outlet pressure can be maintained by using dampers in the flue gas duct, especially when multiple chillers are connected to the same chimney.
l Sharp bends and other fittings causing back pressure should be avoided. The chimney height should be based on the sharp bends and the horizontal length of the duct.
Site Unloading And Installation
l For unloading purposes, use the lifting shackles provided on the chiller. Rigging from any other point on the chiller can damage the unit and cause personal injury.
l Use proper sized hooks/ slings and approved methods for lifting the chiller.
l Lift the chiller simultaneously from all four corners, while keeping the unit level with the ground.
l Proper care should be taken while hooking up the shackles near the pipes. (Refer figure) Rigging and shifting to the foundation
l Every care should be taken to prevent damage to To avoid any damage, the chiller should be rigged with interconnecting pipes, control panel and chiller care to its ultimate location. A plate should be placed mounted panel.
beneath the saddles of the chiller and castors or rollers placed below this plate. The chiller should be pulled gradually from one side using a winch. The wire rope PLACE THE HOOK AS SHOWN used for pulling should be tied to the saddle.
TO AVOID DAMAGE TO THE PIPES Leveling of chiller
Before hooking up the chiller to the external piping, it is very important to level it based on the procedure given below. Proper leveling of the chiller is essential to achieve the rated capacity of the unit. Allowable tolerance (both lengthwise and side-wise) is less than or equal to 1/16 inch per 5 ft. There are four leveling checkpoints provided on the heater. Labeled as A, B, C and D in the figure below, these check points are designated by three punch marks on the tube sheet or shell of the lower shell of the chiller.
Unloading & Installation of Machine (Single
piece)
Procedure for leveling
As a standard feature, the chiller is shipped as a single Fill a clear vinyl hose (diameter of the hose 3/8") with piece. All piping should be adequately supported and water, ensuring that there are no air bubbles in it. Using fitted to prevent any strain on nozzles and connecting point 'A' as reference point, measure the difference in flanges. During installation, sizes of cooling and chilled the water level at the other points (i.e. B, C and D).
water lines should match with those of the connecting nozzles. Their inlet connections should be flushed clean, and the electrical wiring should be verified. The sketch shown below indicates the unloading of a single piece VAPOR ABSORPTION chiller. Note: This is only a diagrammatic representation of the general appearance of the chiller. The actual chiller may be different than what has been shown here.
EcoChill Nxt 37 / 38
Direct Fired Vapor Absorption Chiller Optional Multi-sectional Shipment
The chiller can be shipped in three sections viz. the lower shell assembly, upper shell assembly and the HTG assembly. This is done when there are indications that the chiller's dimensions as a single piece may cause rigging problems (particularly for retrofit jobs). 1. LOWER SHELL ASSEMBLY Leveling calculations are as shown below: Where L= Length of the heater W= Width of the heater In case the tolerance is not met, it can be achieved by inserting a metal shim between the chiller frame and foundation. Metal shim size could be 2" width X 3" length, whereas the thickness of the shims should be in the range of 0.024" to 0.354".
2. UPPER SHELL ASSEMBLY After making adjustments, confirm the leveling of the machine by taking a new set of readings.
Procedure for grouting
After leveling the chiller, it is required to be grouted before the external piping can be connected to it.
This is done by fixing the anchor bolts, by welding washer to the chiller frame and by tightening the bolts.
Storage of the unit
In case the unit is not to be installed immediately, it should be kept covered until its installation. It is recommended to keep the chiller indoors during this period to prevent any damage to it. Nitrogen should not be removed from the heater unit. All the accessories supplied along with the unit should be kept in the same place.
Sustainable Solutions in Energy & Environment COOLING & HEATING DIVISION
Thermax Ltd., India
D-13 MIDC Industrial Area, R.D. Aga Road, Chinchwad, Pune 411 019, India.
Tel : 00-91-20-27475941, Fax : 00-91-20-27475907 Tel : 00-1-248-4743050, Fax : 00-1-248-4745790 www.thermax-usa.com
Thermax Europe Ltd., UK
Tel : 00-44-1908-378-914, Fax : 00-44-1908-379-487 Cooling & Heating Engg. Co. Ltd., China Tel : 00-86-21-64483996, Fax : 00-86-21-64483997 www.thermax-china.com
Thermax do Brasil
Tel : 00-55-21-25169227, Fax : 00-55-21-25169226 Email: www.thermaxdobrasil.com.br
Thermax Rus Ltd., Russia
Tel : 00-7-095-9350490 / 91, Fax : 00-7-095-1347410 Email: [email protected]
Thermax Ltd., UAE
Tel : 00-971-4-8816481, Fax : 00-971-4-8816039 Email: [email protected], [email protected]
Thermax Ltd., Saudi Arabia
Tel : 00-966-3-8575056, Fax : 00-966-3-8575068 Email: [email protected]
Thermax Ltd., Kenya
Tel: 00-254-204440233, Fax : 00-254-204451919 Email: [email protected]
Thermax Ltd, Nigeria
Tel: 00-234-8022908770, Fax : 00-234-14936187 Email: [email protected]
Thermax Ltd., Thailand
Tel : 00-66-2-6555790, Fax : 00-66-2-6555791 Email: [email protected]
Thermax Ltd., Malaysia
Tel : 00-60-3-21669801, Fax : 00-60-3-21669802 Email: [email protected]
Thermax Ltd., Indonesia
Tel : 00-62-21-83793259, Fax : 00-62-21-83793258 Email: [email protected]
Thermax Ltd., Philippines
Tel : 00-63-2-9296964, Fax : 00-63-2-9296982 Email: [email protected]
Thermax Ltd., Bangladesh
Telefax : 00-880-29885823, Mob : 00-880-1912008882 Email: [email protected]
Thermax Ltd., Srilanka
Tel: 00-94-777769126, Fax : 00-94-112533217 www.thermaxindia.com
In view of our constant endeavour to improve the quality of our products, we reserve the
right to alter or change specifications without prior notice. All photographs shown in this
publication are representative in purpose, and to be used for reference only. For actual
details and specifications, please refer to Thermax offer document

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