Integrated Temperature and Humidity Control: A Unique Approach

Abstract

During hot and humid periods, a comfortable indoor environment can be attained only by controlling both the dry-bulb temperature and the humidity in the space. Conventional thermostats control the ON/OFF status of a cooling plant to maintain only the dry-bulb temperature within the conditioned space. This can result in the space dew-point temperature increasing to uncomfortable levels, especially during cool and humid times of the day and/or when there is high latent gain. Consequently, the occupant must resort to undesirable and inefficient interventions (e.g., manually lowering the space dry-bulb temperature set point) to "sweat out" the water from the air. An innovative controller, the Integrated Temperature and Humidity Controller, has been invented for controlling both the dry-bulb temperature and the absolute moisture content of the air in a conditioned space. These new algorithms have been implemented in a product prototype, and limited field tests have been performed. Preliminary results confirm the expected operation and performance of the controller and its robustness and are extremely encouraging.