Book - School of Science and Technology

116 Survey of heating methodsFactors affecting choiceThe choice of system to be adopted can only be related to the type of building, since whatmay be suitable for a process plant would be out of the question for say a block of flats.Home heatingChoice here may be influenced by personal preference, by the routine of daily occupation,by sales pressure from various fuel interests, by close regard for economy or, where apublic authority is concerned, by what is permitted by various local or national regulations.In an existing building, the choice of system may be limited by the facilities available,i.e. absence of a suitable flue, difficulties in arranging sensible and visually acceptable piperoutes, etc., and the availability, in rural areas, of a public supply of gas or electricity.Direct heating systems using solid fuel fires and stoves involve labour, dust and dirtand, with modern habits of families being out all day, are often inconvenient. Gas andelectric fires are then preferred, but tend to be expensive in running cost. Electric storageradiators offer lower running costs, but provide limited control where occupation isintermittent.Indirect systems for home heating can give whole-house comfort as well as hot waterprobably more consistently than any direct system. The capital cost may be higher but therunning cost less, subject to the vagaries of the various fuel tariffs. The choice of fuel for adomestic indirect system, however, may not always be a matter of cost even supposingthat relative prices were to remain stable. While mains gas is the most common choice, insome rural areas this is not available. In such cases bottled gas, oil or solid fuel may beused.Increasing awareness of energy efficiency and climate change issues has lead to interestin different systems aimed at reducing energy consumption.. Heat pumps. Air-to-air heat pumps have been used in conjunction with warm airsystems as an efficient heat recovery device, but usually require a top-up system aswell. More recent heat pump systems use the ground as a heat source/sink, with theadvantage of being able to provide the whole heating demand. Where reversible heatpumps are used, cooling can be provided in summer in addition to winter heating. Heatpumps are discussed in more detail in Chapter 19.. Combined heat and power. To date combined heat and power installations have beenlimited to district or communal heating systems. Units suitable for individual dwellingsare under development at the time of writing, typically based on stirling engines andintended as a direct replacement for central heating boilers. Chapter 24 provides moredetail on combined heat and power applications.. Solar Heating. Although solar water heating systems have been used to providedomestic hot water for a number of years there has been little progress in the use ofsolar energy for space heating in the United Kingdom. Some experimental systems areunder development aimed at providing space heating as well as domestic hot water,although these usually require a top-up source of energy.In new houses gas fired wet central heating serving radiators has become commonplace. However, some may prefer floor heating in order to avoid the loss of floor or wallspace. In an older house, skirting heating might be thought to be less obtrusive thanradiators provided that furniture can be suitably disposed: radiators might be cheaper.