6.88 total energy input which results solely in an increase in temperature in the conditioned space. Latent heat is that portion which results in an increase in the total amount of water vapor present in the conditioned space. Appendix VI.J, on transpiration and radiation, states that approximately 25% of the solar radiation incident on the colony fields is used in the evaporation of water from the surface and transpiration of water from plant life. This portion of the solar gain is latent heat, 6.28x10 6 watts. The remainder is subject to indirect latent heat gain through the metabolic processes of the colony's living occupants: the colonists, their flocks and herds. Estimating a level of activity for a 1000-person community during a particular design period is not straightforward. First,one might imagine that the design period occurred on a weekend when all 1000 might be engaged in leisure time activities. These range from reading, about 100 watts/person, 33% latent, to bowling, 425 watts, 60% latent (see Table 6.3). A conservative estimate might be 25% of the population engaged in sedentary activities, 45% engaged in low energy leisure activities, 15% in moderately high energy activities and 15% engaged in strenuous exercise. This composite yields an average total heat gain of about 200 watts/person, about 112 of which are latent in nature. The basal metabolism of warm-blooded animals has been modeled as Q = (6.6)w 0 · 75 where Q is the heat in BTU per hour per animal, and Wis the weight of the animal in pounds (6.12). Basal metabolism corresponds to a state of relaxation; therefore, multiplying by 1.5 would yield rates for moderately active mammals. A 50% latent heat factor is applied to these total heat gains. Table 6.4 summarizes these values. Basal metabolism for both sexes of goats was found to be 72 watts, but for chickens and rabbits, two types of species had to be analyzed. Two types of chickens are envisioned: egg-layers for egg production and broilers for direct consumption. The mass of a hen is estimated at 2.5 kg, and the average mass of a broiler over its 3-month lifecycle is .73 kg. The mass of a doe was
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