What is a pond mat?
Typically non-tidal water collectors take the form of closed loop Kensa pond mats constructed of slinky pipe attached to corrosion resistant stainless steel frames which are sunk to the bottom of the water source or secured underneath a floating pontoon.
As with all closed loop systems, the principle of a closed loop pond mat is that at no point does the fluid in the pond mat collector leave the system, it is continually cycled through the closed system.
The benefit of using a closed loop water system over an open loop water system includes a reduced risk of freezing within the heat pump and reduced maintenance, as there is no need for any filtration units.
Pond Mat Case Study
Watch how Keith Clarke transformed his energy inefficient home into a self sufficient money and energy source using his pond, a Kensa ground source heat pump and the RHI. Click here
Pond mats in brief:
- Kensa pond mats are specifically designed to ease installation while maximising the energy absorbed from the water.
- Approx 300m of pipe is secured to a corrosion resistant stainless steel frame which can be weighted and sunk to the bottom of the water source or attached to the underneath of a floating pontoon.
- Each pond mat will extract approx 7kW of energy from the water source.
- Safe food grade glycol and water mix is circulated around the pond mats.
- The water source has to be sufficiently deep to avoid freezing around the pond mat and to avoid any damage from potential boat traffic.
- The height of the pond mat depends on the amount of pipe removed from the top of the mat to act as the header pipes, however this should not be higher than 1000mm.
- To ensure the correct heat is extracted from the water source, it is important that the pond mat is covered at all times.
Water collectors have a number of advantages:
- The heat transfer rate from water is higher than that in the ground;
- The water is in close contact with all of the pipe at all times enhancing it’s efficiency;
- The flow/circulation of water provides constant energy replacement;
- The use of a water source removes the need for digging or drilling, reducing the cost and duration of the installation;
- The return temperature to the heat pump is generally 5-6°C higher than ground collectors, increasing the efficiency of the heat pump.