Enthalpy budget

Let us now explain how important the heat exchangers are in the performance of a DR. The need of precooling of 3He before entering the MC is clear if we consider the enthalpy budget ... 

This forms the basis of constructing an enthalpy budget in which the total enthalpy flux is compared with the scalar heat flux, 7q(W m-3), obtained from dividing heat flow by size (volume or mass) of the living matter. If account is made of all the reactions and side reactions in metabolism, the ratio of heat flux to enthalpy flux, the so-called energy recovery ( Yq/H = Jq/Jh) will equal 1. If it is more than 1, then the chemical analysis has failed fully to account for heat flux and if it is less than 1, then there are undetected endothermic reactions. Account for all reactions may seem a formidable task, but it should be borne in mind that anabolic processes dissipate insignificant amounts of heat compared with those of catabolism and that ATP production and utilization are balanced in cells at steady-state. Catabolism is generally limited to a relatively few well-known pathways with established overall molar enthalpies. So, as will be seen later, the task is by no means mission impossible. ... 

Density calculation of chemically active mixtures relies on mole budgets similar yet slightly more complex than those shown in Table 18.1. The composition will depend on the degree of reaction, which in the ideal case, is determined by the law of mass action. The heat of reaction will contribute to the enthalpy budget in Eq. (18.2). 

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