High Efficiency Water-to-Water Water-Source Comfort System
2 through 6 Tons 60 HZ 20 Tons 60 HZ
The water-to-water WSHP product of fering has now been expanded to in clude an AxiomTM 20-ton system. Similar to a small reverse cycle chiller, a water-to-water heat pump contains a source-side water-to-refrigerant heat exchanger, and a load-side water-torefrigerant heat exchanger. The source for the water-to-water heat pump is typically connected to a boil er/cooling tower, or a ground-source loop system. During the refrigeration cycle, heat is transferred from the source-side heat exchanger to the load-side heat exchanger, or vice ver sa. The load-side heat exchanger pro vides conditioned fluid (hot or cold) to a mechanical device such as radiant systems, hydronic fan coils or fresh air ventilation systems. See Figure 1. The units may be applied in a boiler/ cooling tower setting, in a geothermal closed or open loop application, or in a hybrid application. All units accommodate service access to the controls, and other major com ponents to contribute to greater ser viceability and maintainability of the unit. Each unit is verified for total unit per formance before shipping to insure quality standards are inherent in every unit.
A feature summary for the WPWD units include: 1 High efficiency scroll compressor with vibration mount ing isolation 2 Braze plate stainless steel heat exchanger 3 Small, rack-able units sizes that range from 2 to 6-tons 4 5 50 VA transformer Appliance grade finish
Features for the EXWA 20-ton unit include: 1 High efficiency scroll Compressor with vibration mounting isolation 2 Co-axial heat exchanger (copper or cupro-nickel option is available on the source-side of the unit only) 3 Slender design allows unit to fit through a 36-inch doorway 4 Rack-able, modular design 5 Low pressure drops 6 Microprocessor based 24-volt elec tro-mechanical controls (with 100 VA transformer)
6 Thermal expansion metering designed for 25-120 F range 7 8 1-inch FPT swivel connections Factory installed desuperheater option
Figure 1: Source-side vs. load-side2004 American Standard Inc. All rights reserved WSHP-PRC009-EN
Table of Contents
Introduction Features and Benefits Application Considerations Selection ProceduresAbout the ARI-ISO 13256-2 Standard Model Number Description
2 4 8 14
General Data Performance DataCool and Heat Performance Electrical Performance Antifreeze Correction Factors
18 46 47
Dimensional Data Accessories Mechanical Specifications2 through 6-Tons 20-Tons
50 54 55
Features and BenefitsUnit Description The cabinet, which allows easy access for installation and service is con structed of heavy gauge steel. The finish for unit sizes 2 through 6tons is produced by a corrosion resis tant electrostatic powder paint coating in the color soft dove. The 20-ton unit includes a galvanized metal finish for maximum durability and corrosive re sistive exterior. Each cabinet design accommodates modular racking of the equipment to incorporate multiple unit installations within a tight or constraining space. Before shipment, each unit is leak test ed, dehydrated, charged with refriger ant and run tested for proper operation. The cabinet insulation meets UL 181 requirements. Sound All units are internally walled with 1/2inch thick neoprene backed, acoustical fiberglass insulation to attenuate com pressor noise. Compressors are internally isolated to reduce vibration. A compressor base plate and full-length channel stiffeners are installed to further reduce vibra tion. Compressor All units are equipped with a high effi ciency scroll compressor to aid in the reduction of sound, increases reliabili ty and to provide efficient operation. Refrigeration Circuit The 2 through 6-ton units incorporate a single circuit refrigeration design. All heat pump designs include: a revers ing valve, thermal expansion valve, two water-to-refrigerant heat exchanger (source and load), and a com pressor selected for the optimal efficiency of each circuit. The 20-ton unit incorporates a dual cir cuit refrigeration design, duplicating the major components listed above. The units copper tubing is created from a 99% pure copper formation that4
conforms to the American Society of Testing (ASTM) B743 for seamless, light-annealed processing. The units copper refrigeration system is designed to be free from contami nants and conditions such as drilling fragments, dirt, or oil. This excludes the possibility of these contaminants from damaging the compressor mo tor. Filter Drier Every 2 through 6-ton unit is equipped with a bi-directional filter drier to dehydrate and clean the refrigeration system, adding to the life of the equip ment. Water-to-Refrigerant Coil The water-to-refrigerant coils for the unit includes a brazed-plate design for the 2 through 6-ton equipment, and a co-axial design for the 20-ton equip ment. The braze-plate design (found in the 2 through 6-ton equipment) is construct ed from stainless steel, and provides a large amount of surface area for heat exchange between the water and the refrigerant. See Figure 2. The co-axial design (found in the 20ton design) is a seamless tube-withina-tube construction. The inner-water tube contains a deep fluted curve to enhance heat transfer and minimize fouling and scaling. It is available in ei ther a copper or cupro-nickel (selectable option) on the source-side heat exchanger, and a copper only on the load-side heat exchanger. The outer refrigerant tube is made from steel material. The coil is leak tested to assure there is no cross leakage between the water tube and the refrigerant gas (steel tube) coil. See Figure 3. Expansion Valve The refrigerant flow metering is made through a thermal expansion valve (TXV). The TXV allows the unit to oper ate with an entering fluid temperature from 25 F to 120 F on the source-side. The valve precisely meters refrigerant flow through the circuitry to achieve
desired heating or cooling. See Figure 4. Unlike cap-tube assemblies, the TXV allows the exact amount of refrigerant required to meet the heat exchanger load demands. This precise metering increases the overall efficiency of the unit.
Figure 2: Braze-plate heat exchanger
Figure 3: Co-axial heat exchanger
Figure 4: Thermal expansion valve
Features and BenefitsSchrader Connections The connections for the low and high side of the refrigeration system are lo cated conveniently on the units right side for the 2 through 6-ton units, and behind the front, refrigeration access panel for the 20-ton unit. SIDE VIEW Water Connections The water-in/water-out connections to the water-to-refrigerant heat exchang ers are located on the units right side for the 2 through 6-ton units (See Fig ure 5), and on opposite ends for the 20-ton equipment. The source-side, water-to-refrigerant connection is lo cated on the unit front, while the loadside, water-to-refrigerant connection is located at the units back for the 20ton unit. See Figure 6. The fittings for the 2 through 6-ton equipment include a 1-inch, brass swivel, female pipe threaded connec tion. Both the source and the load-side water connections are located on the units right side. The 20-ton connections are located in ternal to the unit to help alleviate damage to the water copper piping during shipment or job storage of the units prior to installation. Fittings for the load-side and source-side connections are FPT (female pipe threaded). Reversing Valve A system reversing valve (4-way valve) is included with all heat pumps. This valve is piped to be energized in the cooling mode to allow the system to provided heat if valve failure were to occur. Once the valve is energized for cooling, it will remain energized until the control system is turned to the OFF position, or a heating cycle is initiated. See Figure 7. Domestic Water Heating Coil (option) A hot water heater connection or des uperheater option is available on the 2 through 6-ton equipment. With this option, excess heat that would nor mally be rejected by the cooling tower, or earth-coupled heat exchanger may
be used to heat water, reducing the amount of electricity or gas consumed by your hot water heater. In summer months, your hot water is virtually free. Year-round, these systems make abundant hot water abundant and are up to 30% less expensive. Standard equipment employing the desuperheater option includes: a des uperheater heat exchanger, circulating pump, entering water temperature de tector (125 F stops pump), discharge refrigerant temperature detector (145 F starts pump), fuse, and a water heater hook-up kit. The circulating pump moves water through the double walled desuper heater heat exchanger. It then returns the heated water to the water tank. This water is heated by the superheat ed refrigerant discharge gas from the compressor, allowing heat energy, typically dissipated through a cooling tower or ground loop, to be utilized as a cost savings. Accessible Unit Control Box The unit control box is accessible through the units front access panel on the 20-ton unit, and through the re moval of the diagonal top on the 2 through 6-ton equipment. The 2 through 6-ton equipment is equipped with 24-volt basic controls, while the 20-ton unit is equipped with the deluxe 24-volt control package. Components are easily accessible for service, maintenance and start-up. 24-volt thermostat connection is made at the unit terminal strip located in the left corner of the control box. See Fig ure 8 for unit control box of the 20-ton unit.
Figure 5: Water connections location for 2 through 6-ton equipment