Design of a Heat Pump Based Heater and Dehumidifier Device

Abstract

Many residential building use electrical heaters mainly in bathrooms, even as a supplement heating device. These devices typically operate at very high efficiency, since in most cases, electrical current is converted into Joule-heat by means of electrical resistances. The humidity of the air in bathrooms is often very high. Therefore, it would be useful to apply such heating devices, which not only increase the temperature of the air, but also reduces the absolute humidity of it. If a heat pump is used for heating purposes where both the heat absorber and the heat exchanger are placed in the same airspace, condensation occurs at a temperature below the dew point of the given air condition at the point of heat extraction thus some of the humidity precipitates. Along with this the absolute humidity of the air can be reduced (which is also recommended for hygiene reasons). Furthermore, due to the latent heat released during the condensation a significant excess of heat appears on the heat exchanger, increasing the heating efficiency over 100%. The design and operation of a heat pump heater operating on such a principle is described in this study, addressing the typical air-conditioning parameters, correlations, calculations performed for the design.