Heating Systems. The central boiler plant consists of biomass fired boilers and gas fired hot water boilers, together with the associated piping and pumps. The boiler installation is sized to meet 120% of the base building load. A constant temperature heating circuit with two variable volume pumps serves the fan coil units. Capped outlets are provided from the flow and return heating water risers for extension to the heating coils in each fan coil unit serving the perimeter of the building provided as part of the works covered by the Category ‘A’ Specification. Entry or exit points from staircases or exit corridors to the exterior are provided with electric heaters.
Heating Systems. (i) The New Tower Building will be heated by finned tube heating elements, within a custom architectural enclosure located at the base of the façade wall of each office floor. The system will be fed by supply and return loops serving water risers at the perimeter columns and will be piped in a reverse return arrangement.
Heating Systems. Thermo processing plants are mainly heated by firing systems using gas, oil or solid fuels, or by electric heating systems. The type of heating system used may be determined by the process involved, the availability of fuel or in some casesby the furnace type. In such cases, the total capi- tal cost and energy expenses for operation and ancillary facilities (e.g. the cost of electric power) must be taken into account. There are many different types of electric heating systems for thermo processing plants (resistance heating with elements positioned directly in the furnace, indirect conductive heating, infrared, arc, plasma and induction heating, etc.). It is not possible to make general statements on energy saving that apply to all types of electric heating system, which is why electric heating systems are not considered in greater detail in this sec- tion. The energy consumption can be expressed in kW per tonne of material treated, allowing a comparison between different heating systems. Non-electric heating systems The combustion efficiency is a measure of the energy efficiency of the firing system. The follo- wing basic statements apply to plants heated using fossil fuels: The higher the combustion efficiency ηf, the lower the energy losses of the firing system and the thermo processing plant as a whole. ηf =(PB -PE) / PAwhere:PB = Heating system outputPE = Flue gas lossesPA = Fuel energy inputandQ· w = Wall heat fluxQg = Useful heat fluxQ· v = Preheating heat fluxQ· O = Furnace heat fluxPS = Flue stack lossesFig 3.1 shows the factors influencing ηf. The dia- gram also indicates that ηf can be significantly improved by preheating the combustion air using flue gas losses. Preheating of the fuel is also possible or normal practice with oil and solid fuels, and in some cases with low-CV gas. QwWall heat fluxP