The use of geo-thermal (constant heat ground water) is not a new concept. It has been used around the world for a long time, especially in geo-thermally active countries.
Ground water has a reasonably constant temperature depending on the depth underground. In Perth, at a depth of approximately 50 metres, water temperature is 22 - 24 degrees year-round, whereas deeper wells have a much higher temperature.
The design is based on drilling into this water table, pumping it into a closed loop heat exchanger which transfers the temperature-constant water through the heat exchanger. This secondary water is reticulated around the building and is run through coils located at the outside air intakes for the building and in turn preheats the incoming air in winter or precools it during summer. It is then returned to the heat exchanger and the ground water re-injected into the same aquifer that it came from.
— On a 40-degree day in summer, hot air is cooled to approximately 28 degrees before being cooled further by the chiller;
— On a 6-degree day in winter, outside air is preheated to approximately 17 degrees before being heated further by the boilers;
— This reduces load on both the chiller and boiler, saving energy in the process using pumps powered by solar panels;
— The building to operate with a greater volume of outside air, improving air quality (CO2 content), improving tenant comfort levels;
— No water is wasted as the same quantity of ground water is returned to the ground and the secondary loop is sealed and also does not lose water;
— Installing a second heat exchanger will allow building owners to reticulate to the tenants to feed supplementary air conditioning units which can be charged back to the tenants through smart EMS systems;
— The only energy consumed is minor and it is to drive a small pump to supply the ground water to the heat exchanger and return it to the ground, with a second pump to reticulate the secondary water loop and return it back to the heat exchanger.
The installation of the system involves drilling a bore in or close to the building, a pump to pull the ground water to the surface and a heat exchanger to transfer the sensible heat to the secondary water extract the temperature from the ground water. The other sideof the loop involves a closed loop system that reticulates the water to the outside air intakes either on the roof or floor by floor as the supply pipe rises through the building. After it is reticulated through coils installed in the fresh air intakes, the water is returned via a return pipe to the heat exchanger and the process repeats. The tempered air then runs through the building's air conditioning system, allowing greater use of fresh air at minimal cost.
The secondary, income-generating component involves a similar system that reticulates water to the tenant's various supplementary units where it is metered, with the tenant paying for heated secondary water used.