Update Bulletin No. 458 www.dulley.com T hank you for your interest in writing to me about devices to improve your summer comfort and save energy at the same time. One of the best devices to accomplish this is a Jim Dulley heat pump water heater (HPWH). What one does is draw heat from the room air and then transfers this heat to the water in the water heater tank. As a result, the air in the room (it can also be ducted to other areas) is cooled and dehumidified. If you now have an electric water heater, installing one may make good economic sense and provide a reasonably quick payback. If you have a gas water heater, it probably will take a longer time period to payback its initial cost. The E-Tech HPWH’s made by Applied Energy Recovery have been available for many years and have proved performance. If you live in a warm climate and use a central air conditioner, a desuperheater unit might be a good choice. See below to estimate about how much you might save by using one. Desuperheaters work by using the heat from the hot air conditioner refrigerant to heat your water instead of just losing it outdoors. In a freezing climate in the winter, it is important to care for the unit properly to avoid freeze damage if water is left in the heat exchanger. The various designs have different methods for taking care of this problem. All of the designs that I have listed are equally effective. Almost all of the geothermal heat pump manufacturers offer optional desuperheater coils for their whole-house systems. Several of them also sell stand-alone geothermal water heaters. For one of these to pay back quickly, you should have a large family with high hot water usage patterns. There are several other efficient methods to improve your indoor comfort. Adding a dehumidifying heat pipe Z-Coil, by Heat Pipe Tech., to your existing air conditioner can lower the humidity level indoors without sacrificing efficiency. Another option is the Santa Fe, by Therma-Stor, that uses a super-efficient dehumidifier to dry the air. It can also bring in fresh outdoor air efficiently. How Much You can Save with a Typical Heat Recovery Desuperheater Unit An average family can save 20% to 40% on annual water heating cost; and improved cooling performance from an air conditioner or heat pump. This will lower your utility bills and provide greater peak cooling capacity on the hottest Your actual savings depends on several factors. They include — 1) How many people live in your house. 2) How much hot water you use each day. 3) What time of day you use your hot water. 4) How much your electric company charges per kilowatt hour. 5) How long your air conditioner or heat pump runs each day. 6) How big and how efficient are your air conditioner or heat pump and your water heater tank. As you can see, the number of factors and their interaction make it very difficult to precisely Hot Water Cost and Savings — Table 1 Family Size Daily Hot Water Usage A/C Size Annual Water Heating Cost per Kw 8.0¢ 8.5¢ 9.0¢ 9.5¢ 10.0¢ predict the actual cost savings, but these compiled results from actual home installations will give you a rough idea of “typical” costs and savings. To get an idea of the approximate savings you can expect from your heat recovery unit, use tables 1 and 2 to estimate the water heating savings and air conditioning performance improvement savings. AirConditioning Improvements Savings — Table 2 8.0¢ 9.0¢ 10.0¢ $11.50 $13.00 $14.50 2 40 gal. $239 $254 $269 $284 $299 3 ton 3 55 gal. $329 $350 $370 $391 $412 4 ton $15.50 $17.50 $19.50 4 70 gal. $419 $445 $471 $498 $524 5 ton $19.50 $22.00 $24.50 5 85 gal. $509 $541 $572 $604 $636 6 100 gal. $599 $636 $673 $711 $748 The annual cost includes both heating up cold water to replace the hot water you use and the loss of heat from your water heater and piping between your uses of hot water. Calculate the savings by multiplying the annual cost figure from the table by the fraction of the year that you operate your air conditioning (i.e. 6/12 or 8/12 or 4/12 etc.) Payback Example — for a family of 4 with a 3 ton A/C, 6 months of cooling and 9.0¢ per KwH electricity Average installed cost of heat recovery $600.00 Less: Hot water savings (6/12 x $471 = 235.50) 235.50 Less: A/C improvement savings (6 x $13 = $78.00) 78.00 Net First Year Cost $286.50 The table assumes 8 hours of air-conditioning per day on a SEER 9 unit and sufficient hot water usage to keep the heat recovery unit running. Older, less efficient units will increase the rate of monthly savings. The newest super-high efficiency units will tend to reduce the savings. Calculate savings by multiplying the monthly figure from the table by number of months per year that you run your air conditioning. These savings result from the freon refrigerant being precooled when it first goes through the desuperheater to warm the water. Since some heat is already removed, there is less heat transfer load on the outdoor condenser coils. Since newer, efficient central air-conditioners have very large condenser coils to start with, the savings with a newer model is less than for an old one. Selected Manufacturers of Devices to Cool Home/Heat Water for Better Comfort APPLIED ENERGY RECOVERY SYS., 6670-A Corners Industrial Ct., Norcross, GA 30092 - (770) 734-9696 www.aeretech.com type - add-on remote HPWH heat source - room air *coefficient of performance (efficiency) - 3.5 model - E-Tech WH-6BX-1 heating capacity - 6,000 Btuh cooling output - 4,000 Btuh dehumidification - 1.0 pint/hr. hot water recovery rate - 10 gal./hr. dimensions - 15.6" × 8.5" × 26" high features - This add-on HPWH has a tube axial fan so the cool, dry air can be ducted to other rooms, into your central duct system or vented outside. There is an automatic freeze-protection switch-over to resistance heating when the room temperature drops below 45°F. There is a fast recovery option that automatically switches the top resistance element on after high volume usage periods like in the morning. The basic design has been around for many years and is well proven. In the winter, it draws extra heat from your utility/furnace area to heat the water or the electric resistance element in the tank heats the water. This is an ideal size for the typical family. Installation to the existing electric water heater is relatively easy. Price of this model is about $700. * Coefficient of performance (COP) of 3.0 means you get three dollars worth of heat for each one dollar on your electric bills. A higher COP is better. www.dulley.com Update Bulletin No. 458 page 2 APPLIED ENERGY RECOVERY SYS. cont’d. type - add-on (tank) HPWH heat source - room air coefficient of performance (efficiency) - 3.5 model - E-Tech R-106K4 heating capacity - 6,000 Btuh cooling output - 4,000 Btuh dehumidification - 1.0 pints/hr. hot water recovery rate - 10 gal./hr. dimensions - 15.6" × 8.6" × 26" high features - This add-on HPWH mounts on top of the water heater tank to save space and for the best efficiency. This high efficiency results from very little energy loss from the HPWH unit to the water heater tank below it. Since it mounts on the tank, the plumbing to attach it to the water heater tank is more complex than with the WH-6BX1 model, so professional installation is recommended. This unit, like the WH-6BX-1, uses HCFC-22 refrigerant. HCFC-22 has a lower impact on the ozone. Most of its features are also similar and it functions in the same way. All E-Tech models require a standard 230-volt electric line which will be available near the water heater if you have an electric water heater. Price is about $1,000 plus installation. ECONAR ENERGY SYSTEMS CORP., 19230 Evans St., Elk River, MN 55330 - (800) 432-6627 www.econar.com type - add-on remote HPWH heat source - earth coef. of performance (efficiency) - 3.3 model - GD-360 hot water recovery rate - 44 gal./hr. dimensions - 15" × 8.6" × 26" high features - Can be used with a central geothermal heat pump. Prices vary with size and installation details. ENVIROMASTER INTERNATIONAL, 5780 Success Dr., Rome, NY 13440 - (800) 228-9364 www.enviromaster.com type - Integral HPWH heat source - inside house cooling capacity - 3,500 Btuh model - WattSaver first hour rating - 52 gallons dimensions - 22.2" dia.× 60" high features - This model is easy to attach to an existing water heater. It is call “110” because it operates on standard 110-volt house power so no special new wiring is required. It has an eight-foot cord so it plugs into a standard electrical wall outlet. It also dehumidifies at a rate of one quart per hour when it is running. The energy factor (EF) is 2.4. The best standard electric water heater has an EF of .95. It has a seven-year limited warranty. The typical installed price of the unit is about $1,500. ENVIRONMENTALLY ENGINEERED EQUIP., 9852 Monroe Dr., Dallas, TX 75220 - (800) 428-7722 www.heatharvester.com type - desuperheater heat source - hot refrigerant from central a/c pumps - one model - Heat Harvester dimensions - 25" × 12" × 6.5" high warranty - 1 year features - These units are primarily designed for light commercial and commercial applications, but they can be feasible for a very large residential home with an air conditioner of five ton capacity or larger and large hot water needs (large family). (Uses thermistors in the water lines to control the pump. When the water temperature in the tank reaches the desired point, the small pump shuts off. The water pump uses about 60 watts of electricity. Contact the company for prices on specific models/capacities. These units will require professional installation. HEAT PIPE TECHNOLOGY, 4340 N.E. 49th Ave., Gainesville, FL 32609 - (800) 393-3464 (352) 367-0999 www.heatpipe.com type - desuperheater heat source - hot refrigerant from central a/c pumps - none model - Hot Plate (see page 4) dimensions - 22.5" octagon x 2.5" high warranty - 5 years features - This unit is designed to fit underneath an existing electric water heater with minimal plumbing modifications. It uses two threeway valves for flushing and connection to the existing water heater (all hardware and fittings are included in kit. It will heat water up to 160°F, but 120°F is the recommended temperature for the best efficiency and lowest overall water heating costs. Price is $400. type - dehumidifying heat pipe power usage - none warranty - 5 years models - Z-Coil and AHR Modular unit (see page 3) Price of a 3-ton Z-Coil is approx. $870. AHR unit prices vary with size/features NYLE SPECIAL PRODUCTS, P.O. Box 1107, Bangor, ME 04402 - (207) 942-2865 www.nyletherm.com type - add-on remote HPWH heat source - inside house cooling capacity - 7,000 Btuh model - Nyletherm -110 hot water recovery rate - 10 gal./hr. dimensions - 16"×12.6" × 21" high features - This model is easy to attach to an existing water heater. It is call “110” because it operates on standard 110-volt house power so no special wiring is required. It has an eight-foot cord and plugs into a standard electrical outlet. It also dehumidifies at a rate of one quart per hour. It has a one-year limited warranty. The current price of the unit is about $900. THERMA-STOR PRODUCTS, PO Box 8050, Madison, WI 53708 - (800) 533-7533 (608) 222-5301 www.thermastor.com model - Ultra-Aire air flow rate - 220 cfm power usage - 782 watts warranty - 5 years features - This indoor air quality/comfort device (see below) combines fresh air ventilation, air filtration and high-capacity humidity control. The control panel contains a fan/filter switch that allows continuous air circulation and filtration independent of dehumidification. There is a dehumidistat with settings from 20% to 80%. Prices range from $2,000 to $2,300 depending on features and options. They also make a super-efficient large dehumidifier “Santa Fe” which I use in my own basement. TREVOR-MARTIN, 4151 - 112th Terrace N., Clearwater, FL 33762 - (800) 875-1490 (727) 573-1490 www.trevormartincorp.com type - desuperheater models - Aquefier, Dynamax, HotTap heat source - hot refrigerant from central a/c features - This company sells all three models. Although each has a different design, they all function in a similar manner and are priced about the same - $600. The small water circulation pump operates on 230-volts and there are models for straight central air conditioners or heat pumps. To determine which is best for your specific home, contact the manufacturer to discuss your system. WATER FURNACE INTERNATIONAL, 9000 Conservation Way, Ft. Wayne, IN 46809 - (800) 934-5667 www.waterfurnace.com type - geothermal heat pump with desuperheater heat source - earth coefficient of performance (efficiency) - 2.5 to 3.5 model - Premier Series water heating capacity - depends on size dimensions - many models and varies with capacity features - Their desuperheater option is most effective in conjunction with a geothermal heat pump (over 2.5 tons in capacity) using the same ground loop or open water source. This allows it to recapture the heat that the geothermal central conditioner transferred to the ground. Has water temperature settings from 110°F to 135°F. comments - If you do not already have a geothermal heat pump with a ground loop installed to which you can connect an optional desuperheater, the installation costs will be substantial. These geothermal systems are the most efficient air-conditioning systems available. Prices vary depending on size and installation details required for your site. Update Bulletin No. 458 www.dulley.com page 3 Geothermal Heat Pump-A/C Units with Optional Desuperheaters Since the ground stays fairly constant in temperature throughout the entire year, a geothermal heat pump will heat and cool a home about two to three times more efficiently than a standard air-to-air heat pump. Both Econar and Water Furnace offer complete standard geothermal heat pumps with desuperheater coil options to heat your water with the waste heat from your house during the summer cooling mode. During the winter, the heat is drawn from the warm ground loop buried in your yard or well. Econar Geothermal Heat Pump-A/C AHR Modular Air Handler by Heat Pipe Technology Econar also offera stand-alone geothermal water heaters. These are economical methods to heat water using electricity. How an AHR works This is a blower unit, with an optional electric strip heating element in it, that mounted on top of a Z-Coil. This will provide a complete system. It uses the outside heat pump/air conditioner in the cooling mode and the heat pump and/or electric resistance strip heating in the winter. Three sizes range from 2 to 5 tons cooling capacity. How a Z-Coil works The return air from your house is precooled by the heat pipe in the Z-Coil. When this Return precooled air air crosses the a/c 78° cooling coil, it is supercooled for extra moisture removal. This supercooled dry air passes over the other end of the heat pipe and is reheated. No extra electricity is used. Water Furnace Geothermal Heat Pump-A/C Z-Coil only by Heat Pipe Technology Air conditioner evaporator cooling coil Precooled air Supercooled air 73° 53° Dry, air to house 58° Extra humidity pulled out of air Water Heater Efficiency Tips 1) Lower the thermostat to 120 degrees from 140 degrees. This action can save as much as $45 per year and reduce the risk of burns from tap water. 2) Wrap the water heater with insulation. If the water heater is located in an unheated area, wrapping it can save up to $1 per month. 3) Drain a few gallons of water from the bottom of the tank each month to remove sediment. 4) Install heat trap fittings in the cold and hot water pipes at the top of the water heater tank. 5) Fix leaky faucets promptly. As you can see below, a faucet that leaks 30 drops/min. = 84 gal./month = 18 kWh/month 60 drops/min. = 168 gal./month = 37 kWh/month 6) If you are going to be gone for more than three days, switch off the power to an electric water heater at the circuit breaker panel or set the thermostat lower on a gas water heater. Schematic of a Typical Heat Pump Water Features 1) Has high efficiency and reliability. Heater Installation Standard electric water heater Upper heating element is retained HPWH is attached through drain Professional installation is recommended and required by code in some areas Cool, dehumidified air is exhausted into utility room or basement or it can be ducted to another room 2) Is a small size to fit most basements and utility rooms. 3) Tube axial evaporator fan allows cool, dry air to be ducted to other areas or vented outside for fresh air ventilation. 4) It can be installed in many orientations with single coaxial plumbing connections. 5) Automatic switch-over to resistance heating when ambient temperature drops below approx. 42 degrees *. 6) Optional fast-recovery installation automatically switches top resistance tank element on after large water draws to minimize hot water outages. 7) Offers automatic high pressure reset. * At 42 degrees, a switch turns off the compressor and the pump activates the defrost mode. In he defrost mode, the resistance heat operates until either the thermostat is satisfied of the ambient air temperature rises above 42 degrees. The evaporator fan operates in the defrost mode to speed up the defrosting of the coil. Applied Energy Recovery Model WH-6BX-1 Update Bulletin No. 458 www.dulley.com page 4 Hot Plate Heat Exchanger by Heat Pipe Technology Dynamax by Trevor-Martin Corp. Hot Cold water out water in Tempering valve one required Cold water 3-way valve (flush) recommended Heat exchanger T & P valve Hot water tank Hot water Air conditioner Cold water Water pump Compressor Specifications • Dynamax units are housed in a .04 thick aluminum cabinet painted with a scratch resistant enamel. • The drive pump is water lubricated and water cooled. It operates at 3,250 rpm, 1/40 hp, .38 amps on 220-240 volts. It delivers a water flow of 12 gpm and a head pressure of 10 feet of water. • Has an automatic water shut-off at 140° and hot gas control set to 115°F. • Uses all copper heat exchanger to meet HUD and UL standards. Nyletherm 110 HPWH Unit Specifications: Cooling output - 7,000 Btuh when running - heat goes into warming water Recovery - 15 gallons per hour at 120 degree tank water temperature Maximum water temperature - 140 degrees Dehumidification - one quart per hour Electrical Specifications: Volts - 110 Amperes - 7.25 Type - one phase, 60 Hertz Installation Requirements: Water heater tank much be clean with no sediment. The existing water heater tank must be the proper size for your family’s needs. The tank drain valve must be accessible Features: High efficiency, safe, reliable, virtually no maintenance. It can be wall or floor mounted for convenience Installation Hints • Use the Dynamax installation kit (IK-5) in the top or bottom of the tanks. • Take water from the drain and return below relief valve. This method may nt be satisfactory with old tanks because particles in the bottom of the tank are difficult to remove and may clog the lines and pump. • Connecting the water line from the heat recovery unit directly into the hot water line from the tank to the house will cause a lack of hot water and water temperature fluctuations. • Unit should be protected from freezing. Freon in from condenser Solder & insulate Freon out to condenser Heat exchanger 3-way valve (flush) recommended Enviromaster Model WattSaver Full “drop-in” replacement for 50 gallon electric water heater: Microprocesser controoled Same footprint Evapotator Compressor Identical electrical hookup No additional plumbing requirement EF Rating = 2.4 Designed for single trade installation. Removable Uses refrigeration compressor – robust, two-piece proven, inexpensive, and compact, yet shroud for easy access sufficient capacity for meeting most to plumbing water heating demands. Thermostat and electrical Auxiliary electric elements provide controls quicker recovery when demand requires No pumps required wrapper condenser Heat pump unit shipped fully charged coil and operational Design employs a conventional hot water tank; simply make plumbing con50-gallon nections and electrical hookups. water tank Can be installed anywhere in your home. Condensate-free option available Quiet Operation Typical payback from 2-5 years (dependent upon kWh rates and water usFoam age) insulation 7-Year Warranty On Tank and Heat Pump Visit www.dulley.com for a listing of all 194 Dulley Update Bulletins available to order by mail for email delivery.