AC-83-15-4 -- Development of a High-Efficiency, Gas-Fired, Warm Air Heating System Utilizing Heat Pipe Technology PDF

The development of a gas-fired, heat-pipe, warm-air heating system with individual room-temperature controls is described. The design concept is based upon a systems approach that integrates a unique, high-efficiency, heat-pipe, warm-air furnace capable of continuous modulation over a four-to-one ratio, a distribution system with individual thermostatically controlled room diffusers, and a control system designed to provide maximum furnace efficiency at all load levels. With this approach, improved comfort over conventional single-point control systems can be achieved by adjustment of the temperature in each room or area in relation to the activities of the occupants or external load factors. Also, because the average residential temperature can be more easily reduced without adversely affecting occupant comfort, increased fuel economy can be realized.

In the developmental work to date, prototype heating system components have been built and tested. Heat-pipe furnaces rated at 100,000 Btu/hr (29.3 kW) input have been installed in selected field test homes for evaluation and have been life-cycle tested in the laboratory. Operation has been found to be completely reliable with steady-state efficiencies of 86% and seasonal efficiencies only a few points lower.