Air to Air heat exchangers: get fresh air, keep the energy inside
February 4, 2009 § 5 Comments
Homes of today follow a green and expense-cutting trend to reduce energy exchange with the environment, keeping a comfortable temperature inside and some money in the bank. But all that sealing actually makes the stall air inside a health treat to the house inhabitants. It can get very humid, due to the paints that prevent vapor exchange through the walls, VOC (volatile organic compounds – chemicals that offgas from paints, plastics, etc) loaded, naturally occuring Radon (Rn) gasses build up as well as mold and mildew. These problems can be solved by opening windows but all that heat embodied in the air is lost, adding up to the energy bill.
An air to air heat exchanger can solve all these problems by taking comfortable warm air inside the house and exchanging its heat with the fresh, clean air from outside, being capable of a efficiency of 80%. So no need for your HVAC system to operate more as the heat flows out when the windows are open.
There is one issue namely the climate specifics. If the climate is very cold, the air to air heat exchanger can’t perform well and because of the below freeze temperatures outside the humidity of the air can create ice in the system and block air flow. In climates where severe sub-zero temperatures are prevalent, it may be better to consider an underground piped heat exchanger. This system offers the same benefits and functions and works the same way: it just utilizes the constant temperature of the ground to warm or cold the recycled air from the home’s exhaust.
Here’s a sketch from wikipedia that can help understanding how the air to air heat exchanger works:
In the end of this short introduction I will conclude that most of green homes need to install such a ventilation device. All of us like fancy furniture and contemporary designed stuff but one must care for its health even if the fancy thing in this case isn’t visible to friends to showoff.
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