Radnor Park Church – Heating System

Radnor Park Church Clydebank has reduced their carbon footprint from 41.14 tons of C02 a year to 6.43 tons by joining a district heating system. They used the carbon calculator provided by Eco Congregation scotland to determine their carbon footprint. In the words of S.W. Cameron, the church treasurer,

the experiment has been an unqualified success both environmentally and financially.

This initiated a few years ago when Clydebank Housing Association applied for planning permission to build a Combined Head and Power plant (CHP) adjacent to our Church. The plant was designed to produce electricity and useable heat which would be connected to what is known as a district heating system for the seven blocks of flats close to the Church.

I suppose it was fortuitous that I am chief engineer in a company called Doosan Babcock who design and construct major power plants. I recognised that there was potential for the Church heating to be connected to their outlet pipes and I contacted the Engineering Contractor of the plant to discuss the possibility.

The electricity production part of the CHP plant is relatively conventional in that steam is produced in a boiler to drive a steam turbine which in turn drives a generator. The steam at the outlet from the turbine has to be condensed to liquid so that it can be pumped back to the boiler inlet and the concept is to use water from the ‘district heating’ system as a coolant and at the same time the condensing steam heats up the district cooling water to around 100-120°C. From the layout drawings submitted with the planning application I estimated that there was probably ‘surplus’ heat in the system and we would effectively increase the efficiency of the CHP plant if we could connect into it.

The initial assessment concluded that it was feasible and the Contractor agreed to run a pipe from the CHP plant to the Church boundary whilst we investigated the requirements in detail and obtained quotes for the purchase and installation of the equipment.

The plant was designed to supply domestic heating and we had to determine whether it could also provide heating for the church building and four halls. We worked with the contactor to specify a heat exchanger connected to the district heating ‘ring main’ and connect the outlet from it to our heating system, bypassing the existing oil boiler. At the same time we didn’t want to fully disconnect the oil heating arrangement in case we had problems in the future. Fitting control valves and bypass valves made it a more complicated but it has been very successful although we are at the ‘end of the line’ of the district heating system and whilst this has not been a problem it meant that bthe church heating was a little cooler during the recent cold spell due to the people in the flats having their heating on full.

I must admit that the original driver was cost saving in that we were paying around £7,000 per annum for oil and the estimated cost of connecting to the district heating system was around £3,000 per annum. The capital cost of the heat exchanger and the installation was £11,000 so we reckoned we would get ‘payback’ in 3-4 years. As it happens the tariff has been substantially less than the estimate because we are taking the surplus heat and it has been difficult to measure the flow and temperature. As such we have already recovered the initial capital cost.

Installing the heat exchange system has reduced our carbon footprint dramatically since the oil fired boiler was probably the least ‘carbon friendly’ system you could get. There are obviously emissions from the CHP plant which I do not have the figures for but plants of this type have an efficiency of around 70% compared to 40% for conventional plant and it is claimed that they have the lowest carbon footprint of any heating system. Since we are taking surplus heat which would be generated in any case if we did not have the connection I would claim that we now have zero emissions from the Church heating system