It’s always a good idea to look for cost-efficient and environment-friendly methods for generating heat and energy in the home. One of these methods is by ensuring the high heat design efficiency of your heat or thermal recovery system. But wait, what does the term 'heat recovery system' refer to in the first place? As the name implies, a heat recovery system produces and stores hot water or air by transferring heat from a condenser to a cooler medium. It works on the principles of energy recovery. There are different types of heat and energy recovery systems, depending on the source to the recipient: air to air, air to fluid, fluid to air, fluid to fluid.
The heat recovery process enables you to save on energy and cut down utilities costs since the process reduces heating and cooling requirements. To illustrate: excess heat in the form of furnace, boiler and oven exhaust and steam could be utilized instead of being pumped out and discarded. There are different types of products and devices for heat recovery systems including heat pipe heat exchangers, rotary generators, and heat pumps.
In order to maximize the cost-reducing potential of a heat recovery system, it is important that this system’s efficiency is monitored. The efficiency is measured with regard to these factors: temperature transfer, moisture transfer and enthalpy transfer.
The following are ways to check on the efficiency of a heat recovery system:
- Heat exchanger efficiency calculator. A heat exchanger efficiency calculation enables you to calculate efficiency by inputting the following values: outside air before the heat exchange; outside air after the heat exchange, and inside air before the heat exchange. Heat exchanger efficiency calculators are available on different websites.
- Check the indicators. An efficient heat recovery ventilation system should have the following indicators: dry efficiency at 80-90%; power consumption should be at 30-40 watts per hour; and the noise level at 25dB maximum.
- Regularly monitor the system. To ensure that your heat recovery system is working at its peak, it’s important that you clean and monitor its parts regularly. Some steps that you should take include cleaning your filters at least every two months; clearing outdoor vents of obstructions (such as leaves, waste paper, etc); cleaning the heat exchange core (check your owner’s manual to help you do this); servicing the fans and have them professionally serviced annually.
- Check for balance. An efficient heat recovery system should have a balance between air inflow and exhaust flow. To check for this, try this very simple method: create a flow tester using a plastic bag with a twisted wire coat hanger holding it open at the mouth. Afterwards, crush the bag to make it flat. Hold the bag’s opening over your system’s exhaust hood (where the system ducts exit); the incoming airflow should inflate the bag in eight seconds or more (if it inflates faster, then lower the speed of your system and try again). Take note of the speed of inflation. Next, take your inflated bag to the supply hood; the air should get deflated at about the same speed of inflation.
There you have it! These are some methods to ensure that your heat recovery systems are working at maximum efficiency. Regular monitoring and checking will definitely go towards giving you the best value for your money. Good luck!