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as the local authority, large hospitals or a university, all of which can help to provide essential core load for a proposed scheme. It is also important to consider the concentration of heat demand which can accure from such potential customers. Cooling by means of absorption chillers offers a further use for heat, particularly at times when heating is not required.

The heating, cooling and power requirement for buildings can be obtained from previous data, provided the existing building use is to be remain unchanged, or by energy modelling techniques. It is important that all cost-effective energy-saving measures for the building either be implemented, or at least considered, before determining heat demand. The fundamental minimum requirements of the heat demand Assessments are:

• the temperature requirements of the heating system

• the determination of peak heat demands

• annual energy consumption.

These data’s will enable some approximate economic work to commence. However, the revenues from the production of electricity vary with time of day and time of year, and hence the cost of heat production from a CHP plant will also vary over the years. It will, therefore, be necessary to determine a heat demand profile over the year, at least on a monthly basis and preferably weekly. 

Monthly heat demand profiles can be estimated using weather data, together with establishing a hot water energy demand profile. In addition, the variation of heat demands over a 24-hour period will be useful, but these data are likely to be available only if a high level of instrumentation has already been installed within the buildings. The hourly heat demand profile is required so that simultaneous heat and power production can be simulated. For electricity, half-hourly data will normally be available for larger users, and monthly data from bills. Consideration needs to be given to the effect of the following on demand profiles for heat and power:

• metering and charging tariffs — if historical data are based on un-metered heat, a change to metered supply normally leads to significant reductions in heat use.

• there may be cost-effective opportunities to reduce heat demand by adding insulation to the building fabric.

• liberalisation of the electricity market makes it easier to sell electricity directly to residents on community heating schemes.

• use of surplus heat for cooling, particularly in summer, when residential heating requirements are low or zero.

At the feasibility stage these decisions will not have been finalised and it may therefore be necessary to proceed with a range of possible heat and power demands.

3.3: Heating systems within buildings

It is necessary to establish details of existing heating systems within the buildings. Some of these may be unsuitable for connection to CH systems, in which an outline engineering design will be needed for their replacement. 

Where systems are more compatible, their operating temperatures and pressures need to be established together with an 本论文由英语论文网提供整理，提供论文代写，英语论文代写，代写论文，代写英语论文，代写留学生论文，代写英文论文，留学生论文代写相关核心关键词搜索。