| Abstract: | A control system is described, based on a microcomputer, which maintains constant temperature and relative humidity in a controlled-environment laboratory used for research on air-to-water heat pumps. The performance of the control system is measured under both steady-state and changing conditions, and optimum values of the control constants are deduced. The temperature can be maintained at the set value to within 0–1°C, and the relative humidity to within 1 per cent, under steady-state conditions. The effects of transients, such as the starting or stopping of the heat pump under test, or the deliberate changing of the controlled conditions, are studied in detail. In addition, a system is described for controlling the temperature of the condenser cooling water, which can be held to within 0–1°C of the set value. |
