SYSTEM DESIGN REQUIREMENTS

Transcription

1 P a g e 1 SYSTEM DESIGN REQUIREMENTS WFC-S SERIES WATER-FIRED SINGLE-EFFECT ABSORPTION CHILLERS / CHILLER-HEATERS Yazaki WFC-S Series water-fired chillers and chiller-heaters are available with nominal cooling capacities of 5, 10, 20, 30, and 50 refrigerant tons. The single-effect absorption cycle produces cooling capacity at 44.6 F (7 C) outlet chilled water using F (31 C) cooling water (aka condenser water) and when it is energized with heat medium at F (88 C). The actual cooling capacity is highly variable and is dependent upon the actual heat medium inlet temperature and flow rate, the actual cooling water inlet temperature, and the actual leaving chilled/hot water set point. Typically, the cooling capacity will increase at higher heat medium temperatures (203 F (95 C) Max.), higher leaving chilled water set points, and lower cooling water inlet temperatures (75.2 F (24 C) Min.). Cooling water temperatures lower than 71.6 F (22 C) or greater than 89.6 F (32 C) should be avoided as temperatures beyond these limits will decrease the cooling capacity. Since the chiller or chiller-heater is water-cooled, a cooling tower or other heat sink must be provided to remove heat from the condenser and absorber. WFC-S Series are available as cooling-only chiller models in 5, 10, 20, 30, and 50 refrigerant ton capacities. WFC-S Series are available chiller-heater models in 10, 20, and 30 refrigerant ton capacities. The chiller-heaters have a heating function that typically produces heating capacity equal to approximately 138% of the cooling capacity that would have been available with the same temperature and flow rate of heat medium. The heating function will provide, at rated conditions, 131 F (55 C) outlet heated water. Since the evaporator produces either chilled water or heated water, the chiller-heaters can be installed in a two-pipe system where a common water coil provides cooling and heating for the building HVAC system. The cooling and heating capacities are listed below: Specifications WFC- SC5 SC10 SH10 SC20 SH20 SC30 SH30 SC50 Cooling Mbtuh Capacity (kw) (17.6) (35.2) (70.3) (105.5) (175.8) Heating Mbtuh Capacity (kw) (48.7) (97.5) (146.2) When larger cooling capacities are required, multiple Yazaki water-fired chillers and/or chillerheaters may be installed in parallel.

2 P a g e 2 STANDARD SPECIFICATIONS Specifications WFC- SC5 SC10 SH10 SC20 SH20 SC30 SH30 SC50 Cooling Capacity Mbtuh (kw) 60.0 (17.6) (35.2) (70.3) (105.5) (175.8) Heating Capacity Mbtuh (kw) (48.7) (97.5) (146.2) --- Cooling Inlet F ( C) 54.5 (12.5) Temperature Outlet F ( C) 44.6 (7.0) Heating Inlet F ( C) (47.4) (47.4) (47.4) --- Temperature Outlet F ( C) (55.0) (55.0) (55.0) --- Chilled/Hot Evaporator Pressure Loss PSI (kpa) 7.6 (52.6) 8.1 (55.8) 9.6 (66.2) 10.1 (69.6) 6.4 (44.2) Water Maximum Operating Pressure PSI (kpa) 85.3 (588.1) / {High Pressure Option of (979.7) may be available} Rated Water Flow GPM (l/s) 12.1 (0.76) 24.2 (1.5) 48.4 (3.1) 72.6 (4.6) (7.6) Allowable Water Flow Range Water Retention Volume % of Rated Gal (liters) 2.1 (8.0) 4.5 (17.0) 80% - 120% 12.4 (46.9) 19.3 (73.1) 33.6 (127.2) Heat Rejection Mbtuh (kw) (42.7) (85.4) (170.8) (256.2) (427.0) Temperature Inlet F ( C) 87.8 (31.0) Outlet F ( C) 95.0 (35.0) Absorber Pressure Loss PSI (kpa) 5.6 (38.6) 12.3 (84.8) 6.6 (45.5) 6.7 (46.2) 6.6 (45.3) Cooling Water Condenser Pressure Loss PSI (kpa) 5.6 (38.6) Included in Absorber 6.6 (45.5) 6.7 (46.2) 3.2 (21.9) Maximum Operating Pressure PSI (kpa) 85.3 (588.1) / {High Pressure Option of (979.7) may be available} Rated Water Flow¹ GPM (l/s) 40.4 (2.6) 80.8 (5.1) (10.2) (15.3) (25.5) Allowable Water Flow Range Water Retention Volume % of Rated Gal (liters) 9.8 (37.0) 17.4 (65.9) 100% - 120% 33.0 (124.9) 51.3 (194.2) 87.2 (330.1) Heat Input Mbtuh (kw) 85.7 (25.1) (50.2) (100.5) (150.7) (251.2) Temperature Inlet F ( C) (88.0) Outlet F ( C) (83.0) Heat Medium Allowable Temperature Generator Pressure Loss F ( C) PSI (kpa) 11.2 (77.0) 13.1 (90.3) ( ) 6.7 (46.2) 8.8 (60.7) 13.6 (93.7) Maximum Operating Pressure Rated Water Flow PSI (kpa) GPM (l/s) 19.0 (1.2) 38.0 (2.4) 85.3 (588.1) / {No High Pressure Option} 76.1 (4.8) (7.2) (12.0) Allowable Water Flow Range Water Retention Volume % of Rated Gal (liters) 2.6 (10.0) 5.5 (20.8) 30% - 120% 14.3 (54.1) 22.2 (84.0) 39.7 (150.3) Power Supply 115 / 60 / volts AC / 60 Hz / 3-Phase Electrical Consumption² Watts Minimum Circuit Amps Amps Maximum Overcurrent Amps 15 Capacity Control On - Off Width Inches (mm) 23.4 (594) 29.9 (760) 41.9 (1064) 54.3 (1380) 70.3 (1785) Dimensions³ Depth Inches (mm) 29.3 (744) 38.2 (970) 51.2 (1300) 60.8 (1545) 77.2 (1960) Height Inches (mm) 69.1 (1755) 74.8 (1900) 79.1 (2010) 80.5 (2045) 82.1 (2085) Construction Dry lbs (kg) 805 (365) 1100 (500) 2050 (930) 3200 (1450) 4740 (2150) Weight Operating lbs (kg) 926 (420) 1329 (603) 2548 (1155) 3975 (1800) 5955 (2700) Noise Level db(a) Chilled/Hot Water Inches 1-1/4 NPT 1-1/2 NPT 2 NPT 3 NPT Piping Cooling Water Inches 1-1/2 NPT 2 NPT 2-1/2 NPT 3 NPT Heat Medium Inches 1-1/2 NPT 2 NPT 2-1/2 NPT 3 NPT Note: All metric values are calculated from the Imperial values and are only approximate values. 1 - Minimum cooling water flow is 100%. 2 - Power consumption does not include external pumps or motors. 3 - Height does not include the removable lifting lugs but does include level bolts. Width/Depth does not include the junction box or mounting plates. Table 1 - Specifications

3 P a g e 3 WFC-SC5 EQUIPMENT DIMENSIONS (Drawings are not to scale) WFC-(SC,SH)10

4 P a g e 4 WFC-(SC,SH)20 WFC-(SC,SH)30

5 P a g e 5 WFC-SC50

6 P a g e 6 The system components required for application of Yazaki water-fired chillers and chillerheaters are as follows: Heat Exchangers: If the heat source available to energize the absorption chiller is steam, hot gas, or hot fluid that is incompatible with the chiller/chiller-heater, install a heat exchanger to produce hot water (nominal F (88 C)) at the temperature and flow rate required by the chiller/chiller-heater. If higher temperatures of heat medium are to be provided (203 F (95 C) Max.), increase the heat exchanger size accordingly. Install a dump radiator (air cooled or water cooled) downstream of the absorption chiller/chiller-heater to reject excess heat from the system when the chiller/chiller-heater cycles off. A dump radiator may not be required if the heat source, such as hot gas from a microturbine or fuel cell, is modulated and controlled through the hot water heat exchanger. Pumps: Chilled/hot water flow tolerance through the evaporator is 80% to 120% of specified flow. Cooling water flow tolerance through the condenser and absorber is 100% to 120% of specified flow (specified cooling water flow is MINIMUM). o Recommendation: Select a cooling tower and pump for 110% to 120% of specified flow to allow for degradation over time. Ensure that the cooling water pump is located below the cooling tower sump where there is sufficient suction head to prevent cavitation. Heat medium flow tolerance through the generator is 30% to 120% of specified flow. Chilled/Hot Water Piping: Install a flow balancing valve at the chilled/hot water outlet. Install an isolation valve at the chilled/hot water inlet. To protect the chiller/chiller-heater from pressure damage, install a pressure relief valve, set at 85 PSI (588 kpa) maximum, in the chilled/hot water pipe between the chillerheater and the flow balancing valve. Higher pressure circuits are not available. Install an expansion tank and makeup water supply (including makeup water check/pressure reducing valve, pressure gauge, and vacuum breaker) on the suction side of the chilled/hot water pump. Install test plugs (P/T Plug) or thermowells in an accessible location adjacent to the chilled/hot water inlet and outlet connections.

7 P a g e 7 Cooling Water Piping: Except for the WFC-SC/SH10, all WFC-S Series chillers and chiller-heaters will require the field-fabrication and installation of cooling water crossover piping. Install a flow balancing valve at the cooling water outlet on both the absorber and condenser fluid circuits. Install an isolation valve in the cooling water inlet line. It is most economical to install this isolation valve upstream of the split in the cooling water crossover. To protect the chiller/chiller-heater from pressure damage, ensure that the pressure in the cooling water circuit does not exceed 85 PSI (588 kpa) maximum. Higher pressure circuits may be available as a special order option at the time of equipment order. When the cooling tower is installed at the same level as or below the chiller/chillerheater, a check valve should be installed between the cooling water pump discharge and the cooling water inlet to prevent the cooling tower sump from overflowing each time the chiller/chiller-heater cycles off. Install hose bibs between the chiller/chiller-heater and the isolation valve on the cooling water inlet as well as between the chiller/chiller-heater and the balancing valve on the cooling water outlet to facilitate draining the cooling water circuit during the winter. Install fittings in the cooling water piping at points recommended by a water treatment company to connect an automatic water treatment system. A computer-controlled system is recommended over a timed-pulse system. Install a bleed-off line with ball valve in the cooling water pipe near the cooling tower inlet in order to control and adjust the bleed-off rate. Install test plugs (P/T Plug) or thermowells in an accessible location adjacent to the cooling water inlet and outlet connections. If the cooling water temperature is likely to fall below 65 F (18 C) during normal operation, install a 3-way modulating valve to control the cooling water inlet temperature to the chiller/chiller-heater. Heat Medium Piping: Install a balancing valve at the heat medium outlet. Install an isolation valve at the heat medium inlet. To protect the chiller/chiller-heater from pressure damage, ensure that the pressure in the cooling water circuit does not exceed 85 PSI (588 kpa) maximum. Higher pressure circuits are not available. Install test plugs (P/T Plug) or thermowells in an accessible location adjacent to the cooling water inlet and outlet connections. Install a motorized heat medium bypass valve (two-position 3-way ball valve) with limit switches to control the flow of heat medium to the absorption chiller/chiller-heater. This valve MUST NOT MODULATE. Either allow the full available flow into the chiller/chillerheater, or have it bypass the chiller/chiller-heater completely.

8 P a g e 8 If it is desired to control the temperature of the heat medium through use of a mixing valve, do so with a separate control from the heat medium bypass valve. This should be done upstream from the heat medium bypass valve. o WARNING: While it has been tried many times, no known (at the time of this writing) job site has ever been successful at using a single motorized valve to perform both the functions of regulating temperature and diverting flow. While it seems simple on paper, there are NO examples of success in actual application. In each instance, the trouble encountered was only remedied by either abandoning temperature control and using the valve only as a diverting valve, or by the installation of an additional control in order to separate the functions. Absorption Chiller/Chiller-Heater: The chiller/chiller-heater foundation pad must be smooth and level. DO NOT mount the chiller/chiller-heater on inertia springs or any other vibration isolation devices. Most building codes require a floor drain in the mechanical room, usually located near to the chiller/chiller-heater foundation pad. Furnish a domestic water hose bib and a 120 vac duplex outlet near the chiller/chiller-heater for future servicing of the equipment. DO NOT mount electrical disconnect switches, conduit, or any other devices on the exterior panels of the chiller/chiller-heater. Any panel on the unit has the potential to need to be removed in order to service items or devices behind them. Also, mounting items to the cabinet will compromise the NEMA 4 rating. Provide adequate clearance, 40 (1000 mm) front and back, 28 (700 mm) right and left sides at minimum, around the chiller/chiller-heater for removal of exterior panels and service access. 50 ton units are specially designed for Modular Installation with zero clearance between them, if necessary. All cabinet panels between the modules must be removed and then the unit modules may be placed as close to each other as possible. A strip of metal can be used to join the two units together in order to maintain a weatherproof seal. Cooling Tower: Select a cooling tower to reject the heat from the chiller/chiller-heater at the local Wet Bulb summer design temperature. At non-standard operating conditions, the cooling tower must be sized for the new heat rejection requirements of the chiller/chiller-heater (cooling capacity + heat input). The cooling tower capacity required for a single-effect absorption chiller/chiller-heater is typically % the size of that which is required for conventional vapor compression systems. Evaluate the quality of the local city water supply and select a closed circuit cooling tower for locations with poor quality water in order to help prevent excessive scaling and corrosion.

9 P a g e 9 The chiller/chiller-heater can control the cooling tower fan by cycling it on at 84.2 F (29 C) and back off at F (27 C). If a different method of controlling cooling tower water temperature is desired, install a temperature controller in the cooling tower sump to control the cooling tower fan. In cases where the chiller/chiller-heater is not controlling the cooling tower fan, DO NOT install the temperature sensor in the cooling water piping. If the chiller/chiller-heater does not control the cooling water temperature, ensure that the method chosen does not provide colder than 71.6 F (22 C) or warmer than 89.6 F (32 C) cooling water for longer than two consecutive minutes. Cooling and Heating Coils: Select cooling coils based on the capacity available from the absorption chiller/chillerheater at standard chilled water flow and outlet temperature (44.6 F (7 C)). A lower chilled water temperature may be used for coil selection if the resulting lower cooling capacity from the chiller/chiller-heater is adequate for the application. Use the same coil for cooling and heating in a two-pipe system. The same coil that is adequate for cooling at 44.6 F (7 C) at a specified flow rate should also be adequate for heating with hot water of 131 F (55 C) at the same specified flow rate. Select heating coils in a four-pipe system based on the capacity available from the absorption chiller-heater at standard hot water flow and outlet temperature (131 F (55 C)). Glycol Applications: Increase the chilled/hot water flow to help compensate for the reduced heat transfer properties of glycol. DO NOT exceed 120% of specified flow rate for water. Install a flow-setter in the chilled/hot water piping to facilitate accurate flow balancing when using glycol. (A flow-setter is NOT required when water is used because the chiller-heater is flow-calibrated at the factory.) Propylene Glycol is always recommended over Ethylene Glycol. PG is non-toxic and has flow and heat transfer characteristics closer to those of water than EG. If glycol solutions are employed, take particular care so that maximum pressures allowed in a fluid circuit are never exceeded in order to prevent damage to the chiller-heater. Power Supply: Furnish 208vac, 60 Hz, 3 phase power supply to a fused disconnect for all sizes except WFC-SC5. WFC-SC5 accepts vac, 50/60 Hz, 1 phase power so in the US market, a simple 15 amp, 115vac power circuit is sufficient.

10 P a g e 10 External Controls: Install motor contactors with 24vac control coils for the chilled/hot water pump and cooling water pump. These pumps are controlled by relay contacts in the chiller/chillerheater. (DO NOT override these motor controls.) Install auxiliary relays with NC contacts that are initiated by alarm contacts on thermal overloads for the chilled/hot water pump, cooling water pump, heat medium pump, and cooling tower fan. (These contacts must be interlocked with the chiller-heater safety interlock circuits.) Use momentary contacts with minimum 0.5 second duration or use a SPDT relay to control selection of COOL or HEAT mode from a remote control system or BMS. Use a separate set of momentary contacts with 0.5 second duration or use a separate SPDT relay to ENABLE or DISABLE the chiller-heater from a remote control system or BMS. If cooling water remains in a chiller-heater during heating operation, a slug of hot water above 120 F (49 C) may be discharged at the start of cooling operation and could potentially damage the cooling tower fill material. Force the cooling water 3-way modulating valve to divert to the cooling tower sump for a minimum of 1 minute at the start of cooling operation in order to bypass hot water to the cooling tower sump. (As an alternative, use high temperature fill material in the cooling tower.) Design Assistance: For further design assistance on integrating Yazaki water-fired chillers and/or chiller-heaters to utilize waste heat from engines, microturbines, fuel cells, industrial process, or in solar thermal applications, please contact your Yazaki Sales Representative or Yazaki Energy Systems, Inc. Evaporator Pressure Loss Characteristics: Model SC5 SC10 / SH10 SC20 / SH20 SC30 / SH30 SC50 Chilled/Hot Water Cooling Water Heat Medium Flow Rate Pressure Drop Flow Rate Pressure Drop Flow Rate Pressure Drop GPM (l/s) PSI (kpa) GPM (l/s) PSI (kpa) GPM (l/s) PSI (kpa) 12.1 (.76) 24.2 (1.5) 48.4 (3.1) 72.6 (4.6) (7.6) 7.6 (52.6) 8.1 (55.8) 9.6 (66.2) 10.1 (69.6) 6.4 (44.2) 40.4 (2.6) 80.8 (5.1) (10.2) (15.3) (25.5) 11.2 (77.2) 12.3 (84.8) 13.2 (91.0) 13.4 (92.4) 9.8 (67.2) 19.0 (1.2) 38.0 (2.4) 76.1 (4.8) (7.2) (12.0) 11.2 (77.0) 13.1 (90.3) 6.7 (46.2) 8.8 (60.7) 13.6 (93.7)

11 P a g e 11 Standard Rating Data For optimum performance, the chilled/hot water flow should be within 80% to 120% of standard, as indicated by the solid line on the chart above. Standard Rating Data For optimum performance, the cooling water flow should be within 100% to 120% of standard, as indicated by the solid line on the chart above.

12 P a g e 12 Standard Rating Data For optimum performance, the heat medium water flow should be within 30% to 120% of standard, as indicated by the solid line on the chart above. Sound Pressure Levels Sound Pressure Levels in db(a) WFC-SC/SH A B C D Noise Level

13 P a g e 13 Performance Characteristics at 44.6 F (7 C) NOTES: 1. Bold blue lines indicate rated design conditions. Where these lines cross designate the Standard Rating Point. 2. All curves are based on water in all circuits flowing at rated design condition flow rates. 3. Heating Efficiency = 97% 4. Performance may be interpolated but must not be extrapolated. 5. Expanded performance curves are provided for reference only. Contact Yazaki Energy Systems, Inc. to obtain certified performance ratings from the factory or to determine performance at other conditions outside the scope of this publication. 6. Performance data based upon standard fouling factor of ft²hr F/BTU in all circuits.

14 P a g e 14 Heat Medium Flow Rate Correction Chart

15 P a g e 15 Typical System Design: EXAMPLE OF A SINGLE MODULE EXAMPLE OF MULTIPLE MODULES

16 P a g e 16 Typical Piping: Cooling Water Crossover Piping: MODEL COPPER TUBING STEEL TUBING WFC- A B A B SC / /2 SC/SH20 3" 2" 3-1/2" 2-1/2" SC/SH30 3" 2-1/2" 4" 3" SC50 4" 3" 5" 3-1/2" If piping size reduction is required, it should be done at the unit. All sizes listed are minimum sizes. CROSSOVER PIPING NOTES: 1. WFC-SC/SH10 units have an internal crossover and do not require this assembly. 2. Each standard crossover pipe has similar pressure losses for balanced cooling water flow through the Absorber and Condenser. 3. Install flow balancing valves in each circuit for non-standard crossover piping designs. 4. Install cooling water flow and/or isolation valves at least 5 pipe diameters upstream and downstream of their respective T fittings. 5. The crossover pipe configuration must provide clear access to the rear of the chiller for maintenance. BMS Control Options: BMS systems can only control the chiller-heater mode selection and whether or not the unit is to be Enabled or Disabled, as shown below in the function of the ESON relay or, alternatively, by the momentary contacts for terminals C and D. No direct interface with the control boards, logic, or temperature sensors is available. Wiring interface to the BMS is done in the Junction Box, located at the rear of the chiller-heater. All relays and wiring in the diagrams below are Field-Supplied. The possible wiring choices for BMS control are presented below:

17 P a g e 17 WFC-SC/SH USING SPDT RELAY WFC-SC/SH USING MOMENTARY CONTACT RELAY WFC-SH USING SPDT RELAYS WFC-SH USING MOMENTARY CONTACT RELAYS The chiller/chiller-heater will always be in whatever mode was last commanded. Even after extended power failures, the chiller/chiller-heater will automatically resume function once the power is restored. Chiller-heaters may require the ESC relay. Alternatively, chiller-heaters may use momentary contacts to be used on terminals A and B for Cool and Heat mode selection. In cases where no remote control of Cool or Heat mode is possible (SC units) or desired (SH units), the ESC relay is unnecessary. Likewise, momentary contacts for terminals A or B would also be unnecessary.