Most of the housing units use LPG for heating and hot water. They also have relatively inefficient wood burning stoves or open fires as an alternative and electric water heaters as a backup if the gas fails. There are three large 4,000 Litre tanks to supply the LPG, with regular deliveries from Calor Gas – usually monthly, but they can be twice monthly in the winter and every two months in the summer. The gas is carried to all but six of the units, which have electric storage heaters. Each unit has its own meter and central heating system. The original system was installed in the 1970’s, with additions in the early 80’s. Some of the gas pipe work was renewed in 2001. A number of the fuel meters need to be replaced soon.

The current heating situation is relatively inefficient and expensive. There is a piped LPG network to 75% of the houses and associated gas boilers, ranging from efficient combi-boilers to older and less efficient standard gas boilers. For other homes a mixture of electric wall heaters and wood stoves, plus electric emersion heaters are used.

Heat Load Requirements

The annual heat load for the site is calculated at just over 750,000kWh, with a maximum heat load demand of 300-350kW. This figure has been derived from standard heat calculations for the type and age of buildings, as well as checking these against the current LPG, electric and wood heating bills.

Wood Chip Heating System

Modern wood heating systems are an established technology in much of mainland Europe. They are a reliable technology which provides similar convenience to fossil fuel heating systems.

To supply 750,000 kWh of heat per year to the homes and communal space using a high efficiency automatic wood chip boiler, approximately 230 tonnes of wood chip per annum would be required (at a moisture content of 25% i.e. seasoned wood).