Obiettivo The overall objective of the project was to demonstrate the cost effectiveness of a shared solar heating system serving a group of new dwellings with centralised storage and control, of the solar heat. The heating system in each dwelling can be individually controlled. 140m2 of single glazed, flat plate, selectively coated collectors provide space heating and DHW for 8, two person flats and summer DHW for 7, five person houses.The Highlands Close Group Solar Heating scheme has successfully operated for over a year with no significant problems. During the monitored period, from 1st. April 1985 to 31st. March 1986, the total solar energy incident on the plane of the collectors was 134.5 MWh (1011 kWh/m2) and heat transferred to the store totalled 33.4 MWh, representating an annual collection efficiency of 24.9%.Although the seven houses were all occupied by April 1985 many of the flats were vacant during part of the monitored period, in fact, full occupation did not occur until December 1985. This has led to a lower than expected load on the solar system in this first year. Solar energy used during the monitored year totalled 8.84 MWh in the flats and 6.69 MWh in the houses. Thus, the overall system efficiency has averaged 11.5%. It is estimated that the future total annual load on the solar system will rise to approximately 22 MWh (with full dwelling occupancy) and system efficiency to over 16%.The solar system has performed very much as expected and the scheme has been very well received by the tenants (who are not charged for their use of solar energy). Over the monitored period the eight flats have received 34.3% of their space and 33.7% of their water heating from solar. The solar DHW heating supplied to the houses (mainly during the summer) represented 20.6% of their annual DHW load. Fans, collector pump and distribution pump electrical energy consumption has totalled approximately 14.7% of distributed energy giving a COP (solar energy used/electrical energy) of 5.93.The Highlands Close scheme has demonstrated the feasibility of grouped solar heating which has many benefits over small systems installed in individual dwellings.However, one disadvantage of group schemes is that of inevitable heat losses from the distribution pipework ( although a proportion of these losses will be "useful", i.e. they provide heat to the dwellings). Over the monitored period distribution losses represented 26.6% and central storage losses 23.5% of collected solar energy. In a larger (optimal) scheme both these figures would be greatly reduced. Nevertheless, BERG is conducting further research to develop control strategies that minimize these losses in small schemes such as Highlands Close.The concept of summertime exporting of solar DHW heating to dwellings outside the main group has been demonstrated. The relatively low additional capital costs for the pipework, controls, etc. and high DHW loads in the houses has meant that this technique has improved the cost-effectiveness of the scheme as a whole.This demonstration of solar heating serves 15 of the dwellings in an estate with similar units for eventual comparison. Minimal modifications have been made to basic house design so that the results can be generalised. A store and control room has system diagrams and performance results on continuous display. Descriptions and illustrations of the scheme's function, performance and cost effectiveness are presented in a leaflet and in a final report.Specific objectives are to- demonstrate the feasibility of sharing a solar heating system among a group of dwellings including some unsuitable for solar collection by themselves;- show the economies of scale from sharing storage and controls;- illustrate the benefits to system efficiency from levelling out variations in demand amongst a number of consumers;- implement improvements to the MARK I system design adopted in the PCL solar house as highlighted by computer simulation;- take advantage of more sophisticated controls than arecost effective in a single house; and- test the social reactions to shared solar heating.The general principle of operation is that water heated in glazed collectors on the roofs of 7 houses is pumped to a shared central heat store and then distributed to the space and hot water emitters in 8 flats and to the dhw cylinders in the 7 houses to make use of excess hot water in summer.a) Collection: the roof area for collectors is 140 m2 gross, coated absorbers in aluminium strip with copper lined waterways slotted and soldered into preformed nipples on the feeder and header pipes. Recent studies have shown these to be cheaper and perform better than other high temperature absorbers currently available. Header and feeder pipes for each house are coupled to main collection and distribution pipes, all laid to falls to avoid airlocks and to drain down fully. The absorbers are backed by rock-wool mat supported on plywood. A foil-faced felt membrane between the insulation layers sheds any fluid, from condensation or leakage, to the gutter via weep-holes.b) Storage: a steel tank holds 7 m3 of water circulated to the dwellings by a five speed pump, according to demand. The water is returned at one of these levels, depending on its temperature, in order to keep the highest temperatures at the top, using two thermostatically controlled motorized valves. The solar heated fluid enhances this stratification by feeding in through either an upper or lower bank of heat exchangers on the same principle. The tank is insulated with 300mm of glass fibre.c) Emitters: the heat is put through twin coil hot water cylinders in the 15 dwellings which have gas boilers as auxiliaries. The flats have fan assisted warm air units between bedrooms, living room and hall. The controls allow the solar heat to pre-heat and the auxiliary gas to 'top-up'. But these can be over-ridden by the tenants if desired. Programma(i) ENG-ENALT 1C - Programme (EEC) of financial support for projects to exploit alternative energy sources, 1979-1984 Argomento(i) 3.1 - THERMAL Invito a presentare proposte Data not available Meccanismo di finanziamento DEM - Demonstration contracts Coordinatore POLYTECHNIC OF CENTRAL LONDON Contributo UE Nessun dato Indirizzo MARYLEBONE ROAD 35 NW1 RLS LONDON Regno Unito Mostra sulla mappa Costo totale Nessun dato
