Cooch Lecture – 27th November, 1992.
“Energy Conservation and Management in Commerce and Industry.”
T. Perera & A. Hall – Seeboard.
The first part of the presentation was delivered by Mr. T. Perera and dealt with Commercial applications. He took a range of commercial buildings and showed how energy management techniques could be applied to them.
His talk was divided into the following parts:-
1. An approach to the heating and cooling of buildings with the “Green Issues” in mind.
2. Introduction to Energy Efficient Design buildings.
3. The vapour compression cycle of refrigeration.
4. Packaged air conditioning units.
5. Split air conditioning units.
6. Geared heat pumps systems and applications.
7. Air conditioning of swimming pools.
8. Air conditioning using ice storage and geared heat pumps.
Mr. Perera commented that all environmental engineering applications applied to buildings should keep the green issues in mind. The emisions
of C02 and CFC’s should be kept as low as possible and energy conservation must be given top priority. By designing heavy thermal mass buildings the need for air conditioning can be avoided. Mechanical cooling need only be used as a last resort.
The concept of Energy Efficient Design (EED) buildings was launched in 1987 by the ESI to promote energy efficient buildings. The specification was modelled on the Danish building regulations and was far more stringent than the current UK building regulations.
An important feature of the EED concept is to construct a building with heavy thermal mass. Such a building will smooth out temperature fluctuations, reduce the need for cooling and enable a large proportion of any pre-heating to be supplied on off-peak electricity. Fresh air can often provide the answer to any cooling problem. If it is necessary to provide mechanical cooling this can be economically achieved using a heat pump. The refrigerant recommended for this equipment is R22 which is ozone friendly. The speaker explained how with the addition of a reversing valve the heat pump could provide both heating and cooling. He then explained the various heat sources and heat sinks for use with heat pumps and described how coefficients of performance (COP) of between 2 and 5 can be achieved.
A simple air conditioning application for the heating and cooling of a single room was described with the aid of diagrams, and we were shown how
the system would operate in summer and winter together with approximate capital and running costs.
The next subject dealt with was the geared heat pump, which comprises a cross flow heat exchanger and a small heat pump coupled together as a
composite unit. In the heating mode the plate heat exchanger recovers heat from the exhaust air and pre-heats the incoming fresh air. This device, a Danish invention, is now finding applications here. COP’s of 6 can be achieved. Examples can be seen at British Airways Heathrow, St. George’s Hospital Wandsworth and at Seeboard Crawley.
Mr. Perera then went on to describe applications in the leisure industry, with a detailed look at a sports complex at Sevenoaks. A heat pump heat
recovery system was installed to maintain conditions in the pool hall and water and operation COP’s of in excess of 5 were obtained. The energy savings over a conventional system were in the region of £25,000 a year.
The next topic our speaker introduced was the concept of ice storage which is now increasingly being used in air conditioning. By using the latent heat of fusion of ice substantially more cooling can be stored in a given volume. The storage ratio of volume of water to ice is 10 to 1 for air conditioning applications. The various stratagies for employing ice storage were then described in detail and information given on the various technical methods for producing and storing ice. Examples were given of installations employing ice storage at The Inn on the Park, London and the Nationwide Anglia Building Society, Northampton.
Mr. Perera introduced a new concept of an ice storage system working in conjunction with a geared heat pump and an energy ceiling using a two pipe change over system. He emphasised the need for a heavy weight building for this concept to succeed. The energy ceiling was a form of plastic hot- water radiator, based on a Swedish design, now manufactured in the U.K.
When used for heating, warm water passes through the panels to maintain an average surface temperature of 25 deg. C. For cooling, cooled water passes through the panels to maintain an average surface temperature of 15 deg.C.
The system supplying the ceiling panels is of the two pipe type which performs well in a heavyweight building. The chiller should be an air to water heat pump. When cooling the heat pump acts as a chiller making ice using night time electricity. When the building requires cooling energy is extracted from the ice storage and supplied as cooled water to the energy ceiling. For heating it operates
as an air to water heat pump providing warm water to the energy ceiling.
The speaker then combined the various components in a typical installation and gave a detailed description of how they can produce a highly energy efficient building at a reasonable price both in terms of capital investment and running costs.
In concluding his presentation he summarised the benefits of the energy ceiling system with ice storage and geared heat pumps in a highly insulated building having a heavy thermal mass as:-
1. Controlled fresh air supply for the occupants.
2. Reduced electrical load for the building.
3. Reduced mechanical cooling requirements.
4. Lowest capital costs.
5. Lowest building energy consumption and costs.
Mr. Perera then introduced the next speaker Mr. A . Aldridge who dealt with electrical applications to industry which have helped companies to dramatically increase energy efficiency and their business performance.
Mr. Aldridge described the service that Seeboard offer all their customers. In the industrial sector they have endeavoured to keep their customers updated on new and innovative techniques to ensure they get the very best from the use of electricity.
He described the 1992 SEEB Business Energy Awards scheme and the previous PEP awards for manufacturing industry and the BETA awards for commercial buildings. The speaker explained that since the introduction of these schemes in the mid-80’s they have performed the valuable function of identifying many cases where the adoption of electrical techniques has enabled customers to improve their energy efficiency and business performance.
A number of case histories were then described in detail with illustrations taken from industry in the South East. Typical of the case histories Mr. Aldridge described are as follows:-
Goldwell Hair Cosmetics at Eastbourne where by using a heat pump and additional storage tanks one for hot water and the other for cold, brought
about a reduction in energy consumption of 74% and enabled throughput in the factory to be increased by 237%. The pay back on the capital investment was 10 weeks.
Another energy efficient system was at Redlands Beare Green Brickworks where the installation of a dehumidifier to replace a gas fired dryer resulted in wastage on special hand made bricks being reduced by from 50% to 5%, production capacity being increased by 90% and energy consumption cut by 60%. Pay back on material savings alone was 7 months.
Spun Concrete at Rye, manufactures circular steel reinforced concrete pipes. Replacing two coal fired boilers for steam generation by an 750Kw electrode boiler reduced energy consumption by 80% and achieved production savings of £21,000.
Using induction heating to replace a steam oven for heating metal drums containing chemicals at Comma Oil increased blending throughput from 5 to 20 drums per day and reduced annual energy costs from £7,200 to £1,200.
The speaker gave numerous other examples in a similar vein.
Mr. Aldridge concluded his talk by saying that the case histories told their own stories and gave excellent examples how electrical energy efficient techniques can transform many industrial processes and make them more profitable.
After the speakers had dealt with a number of questions from the audience; Mr. J. Morgan, after relating to his experience with air conditioned buildings, expressed a vote of thanks to the speakers for their presentation.