scope:

This appendix presents methods of determining efficiency ratings and operating costs of gas-fired, heat pumps for space-conditioning performance. The procedures in this appendix apply to factory-made, space-conditioning, unitary heat pumps which utilize gas as the primary fuel. This includes engine-driven heat pumps, absorption-cycle heat pumps, desiccant-type heat pumps, and other gas-fired heat pumps. The heat source/sink for the heat pumps may be outdoor air, ground water, or closed-loop water. The heat pumps provide the functions of year-round space conditioning either by direct heating and cooling of air or indirectly by the production of heated and chilled water. The heat pump may include other functions.

Appropriate portions of this appendix can be applied to heat pumps which have a gas input that varies so that the output matches the cooling or heating load, to heat pumps which have a single level gas input which varies as a function of ambient conditions, to heat pumps which have a constant gas input regardless of load or ambient conditions, and to heat pumps with several discrete levels of gas input.

In addition to applying to heat pumps which provide year-round space conditioning, portions of this appendix can be applied to heat pumps which provide space cooling only or space heating only. Also, the procedures in this appendix are provided for evaluating and rating water-cooled air conditioners and water-cooled chillers which reject condenser heat with a cooling tower, air- and water-cooled condensing units, and desiccant ventilation-air dehumidifiers.

Section 2 covers calculation procedures for determining steady-state efficiency ratings for the appliance operating in the cooling mode.

Section 3 covers calculation procedures for determining steady-state efficiency ratings for the appliance operating in the heating mode.

Section 4 covers calculation procedures for determining cooling-mode energy costs and efficiency ratings for appliances suitable for installation in residential applications. The steady-state cooling ratings from Section 2 are required as inputs for these determinations. A sample calculation is provided in Annex A.

Section 5 covers calculation procedures for determining heating-mode energy costs and efficiency ratings for appliances suitable for installation in residential applications. The steady-state heating ratings from Section 3 are required as inputs for these determinations. A sample calculation is provided in Annex B.

Section 6 covers calculation procedures for determining annual energy costs for appliances suitable for installation in residential applications.

Section 7 covers calculation procedures for determining cooling-mode energy costs and efficiency ratings for appliances suitable for installation in commercial applications. A sample calculation is provided in Annex C.

Annex D provides procedures for determining the annual energy consumption of other residential space-heating/space-cooling appliances.