Ground Source Geothermal Heat Pumps and Warmboard

Fri, 05/03/2013 - 10:04

For many homes, electricity is a feasible fuel source for heating water in a radiant floor heating system. Investing in a ground source geothermal heat pump can be a practical solution for those who want low energy bills, low energy consumption, and are attracted to the concept of using a renewable energy source.

How Does It Work?

These systems work like refrigerators in reverse during winter months, as ground source heat pumps gather warmth from the earth and use a compressor in order to provide a source of energy for a house. The ground source heat pump is made of three parts and uses a combination of energy-producing and energy-storing technology. The ground loop gathers heat from the ground, the heat pump moves the fluid through the pipes and the distribution system delivers this warmth throughout a home.

The delivery system is where many people see a lack of efficiency emerge, as homes without a radiant heating system are not able to see the full benefit of using this type of energy source. A radiant heating system helps to distribute the warmth around a house in a more efficient manner, allowing a homeowner to really save when it comes to heating their residence. While other products may still require a significant use of energy to provide warmth, a radiant heating system uses a small amount of energy and an efficient delivery system to limit costs and consumption levels.

The purpose of integrating a heat pump is to increase efficiencies. The heat pump has the ability to take one unit of heat, (one Kilowatt hour, 3413 Btu’s) and convert it to five units of heat (five Kilowatt hours, 17065 Btu’s). This example of a heat pump transferring one unit of heat and converting to five units of heat is referred to as a “Coefficient of Performance (COP) of five”. A standard electric boiler or water heater has a COP of one. The COP of a heat pump can vary from one to six.

When a heat pump is in operation the coefficient of performance (COP) will increase as the design water temperatures decrease. The low water temperatures of a typical Warmboard radiant heat system works seamlessly with ground source geothermal heat pumps and allows for maximum efficiency.

A Typical Example

An 80 gallon storage tank of water is heated by a ground source heat pump. The required water temperature for floor heating is 100 degrees. When this storage tank reaches its temperature set point of 100 degrees the heat pump will shut down. During this operational mode the heat pump will experience high efficiency ratings of COP’s of 4.8.

“Heat pump COP”= Coefficient of Performance “LWT” = load water temperatures. “Entering source fluid temperature” = ground source loop of 50* used in this example.

If the same 80 gallon storage tank is requiring 130 degree water temperatures instead of 100 degrees, the heat pump will keep running to attempt to reach a set point of 130 degrees. At this point in operation the heat pump efficiencies go down to 3.4 COP’s. In some applications the heat pump will be unable to provide these higher water temperatures and an electric boiler or heating element will be required to supplement the heating demands.

In this common example above, the heat pump will use 29% less electricity when comparing the design water temperatures of 100 degrees to design water temperatures of 130 degrees.

Warmboard radiant subfloor is the ideal heating panel to interface with a water to water ground source geo thermal heat pump. The low water temperatures of 100 degrees are common for many Warmboard projects, while many other radiant floor methods require water temperatures of 20 to 60 degrees higher.

Warmboard is a proven product that has set the highest standards in the industry when evaluating efficiency, comfort and response time. What makes Warmboard so efficient? Click here to find out.