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The Carnot method is an allocation procedure for dividing up fuel input (primary energy, end energy) in joint production processes that generate two or more energy products in one process (e.g. cogeneration or trigeneration). It is also suited to allocate other streams such as CO2-emissions or variable costs. The potential to generate mechanical or electrical work (exergy) is used as the distribution key. For heat this potential can be assessed the Carnot efficiency. Thus, the Carnot method is a form of an exergetic allocation method. It uses mean heat grid temperatures at the output of the process as a calculation basis. The main application area of this method is cogeneration, but it can also be applied to other processes generating a joint products, such as a chiller generating cold and producing waste heat which could be used for low temperature heat demand. The Carnot method's advantage is that no external reference values are required to allocate the input to the different output streams; only endogenous process parameters are needed. Thus, the allocation results remain unbiased of assumptions or external reference values that are open for discussion. == Fuel allocation factor == The fuel share ael which is needed to generate the combined product electrical energy W (work) and ath for the thermal energy H (useful heat) respectively, can be calculated accordingly to the first and second laws of thermodynamics as follows: ael= (1 x ηel) / (ηel + ηc × ηth) ath= (ηc x ηth) / (ηel + ηc × ηth) Note: ael + ath = 1 with ael: allocation factor for electrical energy, i.e. the share of the fuel input which is allocated to electricity production ath: allocation factor for thermal energy, i.e. the share of the fuel input which is allocated to heat production ηel = W/QF ηth = H/QF W: electrical work H: useful heat QF: Total heat, fuel or primary energy input and ηc: Carnot factor 1-Ti/Ts (Carnot factor for electrical energy is 1) Ti: lower temperature, inferior (ambient) Ts: upper temperature, superior (useful heat) In heating systems, a good approximation for the upper temperature is the average between forward and return flow on the distribution side of the heat exchager. Ts = (TFF+TRF) / 2 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Carnot method」の詳細全文を読む スポンサード リンク
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