Ground source heat pumps are becoming increasingly popular. Whilst more expensive than traditional fossil fuel heating systems and their air source heat pump relatives, you can achieve some of the lowest running costs possible using this tried and tested technology. Extracting energy from the ground requires little maintenance once installed, but installation is a disruptive process.

To truly understand if there is a solution suitable for you - and before you dismiss this renewable technology because of the inevitable upheaval created - read this post to better understand the various methods and systems that can be used. There are a variety of ways to harvest energy from the ground in order to feed a ground source heat pump system with valuable natural energy. In this post, we cover the spectrum of options.

Horizontal Collectors

The most traditional of collector types, the horizontal collector consists of continuous lengths of plastic pipe between (25mm – 40mm diameter) being laid out in the bottom of an excavated hole or trench separated by a fixed distance. Imagine a large outdoor underfloor heating system buried in your garden! The pipes are often made from medium density or high density polyethylene plastic, laid around 1.2-1.5m below ground level and will last 50-100 years. Depending on the ground conditions and heat pump size the amount of buried pipe will vary.

As a rule of thumb, and assuming a loam soil, ground loops may occupy an area twice the size of the total floor area of the home to gather energy for the home all year round.

Slinkies are also used and fit into the horizontal collector group. They are made from a similar material to standard horizontal collectors and are often 20mm-25mm in diameter. Unlike standard collectors they come in a continuous coil that is placed in a 1.2m-1.5m deep trench, stretched out and then laid down (a bit like a flat slinky) and pinned in place. Instead of having equally spaced pipework there are many intersections in a single loop and for this reason are not preferred by some installers due to likelihood of premature ground freezing during winter.

The main advantages of slinkies are that they are quicker and easier to install than standard collectors. They also reduce ground works and take up less land space.

Either type of collector loops gather in a sunken plastic or masonry inspection chamber in which they are connected to a main flow and return manifold. This allows low grade heat to be gathered from a large area and yet only two pipes return from the manifold location to the plant room location where the heat pump is located.

As always you have a choice and there is bound to be a ground source heat pump collector solution for you if you would like to go down this route.