Information is power
The Envirosun ‘AS Range’ of solar hot water systems uses a small circulating pump and electronic microprocessor to transfer the heat absorbed by the solar collector to the separate storage tank. The circulating pump draws very little electrical power (less than 28 watts) and only operates when the microprocessor determines that there is a useful gain to be made. The microprocessor takes information from temperature sensors on the solar collectors and in the storage tank. When the collectors are 6oC hotter than the water in the storage tank, the circulating pump is operated. When the differential falls to 4oC or lower, the pump is not operated. The microprocessor also uses the sensor information to control a suite of over-temperature protection modes:
- if the water in the storage tank reaches 70°C, the pump is stopped;
- if the collector temperature reaches 190°C, the pump is cycled on to control the temperature to below 185oC;
- if the collector temperature reaches 200°C the pump is not operated;
- if the tank temperature has risen above 70°C and the collectors are cooler the pump is run.