Earth pipes to improve MVHR efficiencyAir Conditioning without Air Conditioning
A system that supplies cool air in summer without the need for any sort of air conditioning unit and with minimal running cost.
The temperature of the soil at ground level tends to be much the same as the air temperature, give or take, with a slight time delay. But the temperature of the soil at 1.5 or 2m down tends to be pretty static at about 10° C (it does vary throughout the country depending upon location and soil conditions but will be about that). The system adopted by Starkey Systems UK Ltd takes advantage of this fact.
It has been standard practice in this country when installing ventilation and heat recovery systems that the fresh air supplied to the system is drawn in from roof level or certainly above ground. This means that in summer, warm air is drawn in and cooled by the outgoing air until the evening when the summer by pass is activated. And in the winter, cold or cool air is warmed by the out going air.
On hot summer days therefore you have to put up with a very warm house or install an air conditioning unit. Both very expensive to install and even more expensive to run (and increasingly so with rising fuel prices).
The Starkey Systems G2A Heat Exchanger (G2A stands for Ground to Air!!) overcomes both cost disadvantages of the standard air conditioning systems. Firstly the materials cost for the G2A system is about £3000 for a house requiring only one heat recovery unit and secondly, costs almost nothing to run!
What is this system?
The system consists of a single length of pipe made of conductive antimicrobial material approximately 200mm (or 250mm) diameter laid 1.5 or 2m below ground in a loop around the house or in the garden. One end terminates in a stainless steel tower (about one metre high) where the air is drawn in and the other links up with the supply ducting for the heat recovery unit (or vent supply fan).
Of course the advantage of this system is not only cooling in summer but preheating of the incoming air in winter adding to the savings in energy costs.
What is the effect on the air temperature in the house?
As an example, if the outside air temperature is 28° C, the air on the supply side of the MVHR unit will be in the order of 16° C. This is a pretty dramatic cooling effect although you must appreciate that while the incoming air might be that cool, the extent to which it can cool the house is very much dependent upon the house design including solar gain and thermal mass. Equally, in winter the air can be preheated from (as an example) - 5° C to + 4° C. This means that there will never be need to activate the preheating device on the MVHR unit.
This must be the number 1 add-on to any heat recovery system or eco house!
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or call us on 01684 899 017 to find out more
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