A Gas-Fired Heat Pipe Zone Heater

Abstract

A gas-fired vented zone heater has recently been developed by the Altar Corporation for Colorado State University (CSU) under a Gas Research Institute (GRI) contract. The unit war developed for auxiliary heating applications in passive solar buildings. An early prototype was tested at Altas and operated as expected. The final model was shipped to CSU in December 1983 for testing in the REPEAT Facility at CSU. A heat pipe extends through the wall to the outside of the building. It has a modest water charge which can freeze repeatedly with no damage, since the heat pips is only partially filled. Firing efficiency at 4,000 Btu/b (1.17 kW thermal) is approximately 80%. The unit features a 3 foot by 3 foot radiator mounted inside the room to be heated, and is thermostatically controlled. Ignition is accomplished with an electronic sparker (pilot). The radiator typically operates at 150-180°F (65-82°C), and has been operated at between 2,000 and 5,000 Btu/h (0.6-1.47 kW). Results of testing the vented heat pipe zone heater at CSU arm presented. Also, a method for determining the optimal combination of zone heater, passive solar heating and energy conservation measures has been developed. Nomographs have been developed that may be used by a building designer to determine the optimal combination of zone heater size, passive solar system size, and energy conservation measures for given types of passive solar heating systems in selected locations. A representative nomograph is presented along with a design example.