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C1
| C1.1 | Introduction |
| C1.2 | Fundamental considerations |
| C1.2.1 | Legislation |
| • Temperatures in buildings |
| • Reduction of carbon dioxide output – England |
| • Building regulations for the UK other than England |
| • EU building energy regulations. |
| C1.2.2 | Design standards |
| • Fuel systems (oil and gas) |
| • National Standards |
| C1.2.3 | Financial incentives |
| • Enhanced Capital Allowances (ECAs) |
| • Renewable Heat Incentive (RHI) |
| • Climate Change Levy |
| C1.3 | Strategic design decisions |
| C1.3.1 | Comfort |
| • Convective heating |
| • Radiant heating |
| • Temperature variations in the space |
| • Localised radiation |
| • Warm or cold floors |
| • Cold downdraughts |
| C1.3.2 | External design conditions |
| C1.3.3 | Internal design conditions |
| C1.3.4 | Choice of fuels and energy sources |
| • Overview |
| • Grid electricity |
| • Combined heat and power |
| C1.3.5 | Choice of system for different building types and constructions |
| • Offices |
| • Schools |
| • Industrial buildings and spaces with high ceilings |
| • Dwellings |
| • Infrequently occupied buildings |
| • Historic buildings |
| • Highly insulated modern buildings |
| • Poorly insulated older buildings |
| • High thermal mass buildings |
| C1.3.6 | Plant sizing and design margins |
| • Building preheating for intermittent operation |
| • Use of design margins |
| • Load analysis, diversity and plant selection |
| • Standby capacity and resilience |
| • Controllability at reduced output |
| C1.3.7 | Frost protection |
| • Building protection |
| • Protection of systems |
| C1.4 | Types and choice of heating systems |
| C1.4.1 | Centralised versus decentralised systems |
| C1.4.2 | System selection |
| C1.4.3 | Emitters |
| • Convective type |
| • Radiative type |
| C1.4.4 | Distribution media and temperatures |
| • Overview |
| • Water systems |
| • Air systems |
| Further reading |
C1
C1.1 Introduction
This chapter provides an introduction to heating methods and takes a general overview of the purposes of a heating system and how to achieve comfortable environmental conditions in a building. It also outlines the process of choosing a suitable method of heating; alternative distribution systems; alternative fuel and energy sources and the types of heat emitter available to heat buildings.
The selection, design, commissioning, operation, maintenance and management of a building’s heating system is crucial for social, economic, regulatory and environmental reasons. The strategic choices, including the requirements imposed by the intended use of the building, energy and environmental targets, and the legal requirements are dealt with in this chapter.
Heating of buildings is often considered straightforward when compared to air-conditioning and ventilation systems, but there are many options and permutations to be considered. Importantly, these include, first, how to minimise energy use and carbon emissions and, second, how to integrate a mixture of heat sources – both fossil fuel-fired appliances and renewable and low-carbon technologies – to optimise the performance.
Heating systems offer the designer a range of options to minimise energy and carbon emissions by the use of both fossil fuel and renewable technologies
Most space heating systems use a remote heat source such as a boiler, combined heat and power (CHP) plant, district heating or a heat pump to supply heat via a transport medium, usually water but sometimes steam or air, through a distribution network to a series of emitters (e.g. radiators, convectors, fan convectors). Systems utilising a transport medium are known as indirect systems. Alternatively, direct fired systems or direct electric systems can be used, that either rely on radiant effects usually from overhead tubes or panels, or warm air blower systems. Some of these systems actually circulate greatly diluted combustion products into the space and are described in Chapter C6.
The basic components of any heating system are:
– a means of generating heat, i.e. the heat generator and energy source;
– a means of distributing the heat around the building or buildings, i.e. the distribution medium;
– a means of delivering the heat into the space to be heated, i.e. the heat emitter. These can either deliver heat by radiation or convection or a combination of the mechanisms.
Multiple permutations exist in selecting the most appropriate system for the application; fundamentally:
– heat source;
– distribution medium;
– emitter type.
The above gives many possible permutations and options to be considered. Examples include the simple use of electric panel heating, using electricity both as the heat source and distribution medium, to a conventional gas boiler system distributing low-temperature water to a convector system. A more complex system would be one serving various buildings by using oil or gas as the energy/heat source to generate high-temperature hot water for the main distribution, which is then reduced in temperature and pressure to low-temperature water via heat exchangers, to serve systems in multiple buildings.
In modern comfort-cooled buildings, emitters may be integrated into terminal units to provide both heating and cooling. These include fan coil units and, more recently active beams, as discussed in Chapter D1...
