By using the sun’s free energy by installing a solar hot water heater you can reduce your hot water energy consumption and save up to 2 or 3 tonnes of greenhouse gas emissions compared to a conventional electric water heater, so you can imagine the benefits for our future generations and the future of the planet.
Evacuated Solar Tube Solar Collectors vs. Flat Plate Solar Collectors vs. Heatpumps
Solar collectors come in different sizes, types and brands. Making sense out of what is the best for a particular use can sometimes be a little confusing. Hopefully, this brief overview will help you make an informed choice. And, as always, you can call us anytime to discuss your properties application and use.
Evacuated Tube Solar Collectors
Evacuated Tube collectors come in many different brands, they work by absorbing the sun’s energy, trapping it like a giant thermos flask and efficiently transferring heat to the water supply. Evacuated Tubes are glass tubes that are manufactured with a vacuum seal in-between the glass layers, preventing heat loss from convection and radiation. In this type of solar collector, heat is transferred from either a flat or curved copper or aluminum fin attached to a heat pipe located in the evacuated tube. The heat pipe then moves the heat collected in the tubes upwards to a manifold which transfers the heat to the cold water in the tank that has been circulated by a pump to the top of the collector. The heated water is then returned and stored in a storage vessel on the ground.
Most brands are tolerant to frost, hail & freeze resistance to –10°C.
Flat-Plate Solar Collectors
Flat-Plate collectors are the most common type of solar collector for solar water heating sytems, they are used in closed loop and open loop solar systems. These collectors consist of an insulated metal box with either a glass or plastic covering (this is what is referred to as the glazing) and a dark absorber plate usually made out of copper or aluminum. This absorber plate transfers the heat to a tube or a channel where the heat transfer fluid flows, picks up the heat from the plate, and returns it to the storage tank. Flat-Plate Solar collectors are less expensive than the Evacuated Tube collectors giving it a very good price/performance ratio.
Heat Pumps
The basic principle of a Heat Pump water heater is similar to a refrigerator working in reverse. When hot water is drawn off and cold water enters the tank, the thermostat activates a fan, a compressor and a circulator.
Heat from the ambient air is absorbed by a refrigerant gas (evaporate), this refrigeration gas is then compressed using a small compressor which causes the gas’s temperature and pressure to be raised. This heat is then transferred to the water inside the storage tank.Once the heat from the compressed gas has been transferred to the water tank, the gas becomes a liquid again as it has lost it’s heat. This liquid gas then passes through an expansion device and back to the evaporator. The cycle is then repeated until the water in the storage tank reaches the set water temperature.
Minimal electricity is required for the compressor, fan . Some heatpumps will work in temperatures from as low as -10°C up to +40°C during day and night very efficiently without the need for boosting.
