Methods to improve the operating coefficient of performance of heat pump water heaters. [Add-on type]
There are many factors which impact on the operational coefficient of performance of HPWHs. The Energy Factor values derived from the NBS/GAMA tests are not necessarily indicative of field performance. There are additional factors which impact on performance that need to be addressed. Two of these factors are discussed; temperature of inlet water to the heat exchanger (condensers) of heat pump and augmenting the temperature of the energy source. Inlet water temperature to HPWH is believed to be influenced by the water connections between the HPWH and the storage tank, the capacity of the tank with respect o the daily water usage and the control theory employed for the HPWH unit. System designs which promote and optimize batch mode of operation will result in the most efficient operation. Location of tank water connections with add-on HPWH, flow rates (velocity) of circulation water and draw-off, use of baffles and diffusers, size of tank with respect to usage, water flow control valves and electrical controls which restrict operation of HPWH all should be considered. HPWHs are perhaps least efficient when making up standby losses because of the high values of Tii. Small well-insulated tanks should be encouraged. Augmenting the temperature of the entry source, in this case air, with solar energy is discussed. With proper installation, significant gains in operational performance and savings can be achieved by operating a HPWH in a sunspace. 8 refs., 5 tabs.
- Research Organization:
- Cornell Univ., Ithaca, NY (USA). Dept. of Agricultural Engineering
- DOE Contract Number:
- FG42-81R205321
- OSTI ID:
- 5318867
- Report Number(s):
- CONF-830213-3; ON: DE85016324
- Resource Relation:
- Conference: 10. energy technology conference, Washington, DC, USA, 28 Feb 1983; Other Information: Paper copy only, copy does not permit microfiche production
- Country of Publication:
- United States
- Language:
- English
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