Page 347 - Handbook of Energy Engineering Calculations

daytime temperature increase and to store the solar gain for nighttime
heating. Estimate the passive solar-heating contribution for an average
heating season.

Calculation Procedure:

1. Compute the heat loss
The surface areas and the coefficients of heat transmission of collector,

windows, doors, walls, and roofs must be known to calculate the conductive
heat losses of a space. The collector area can be estimated for purposes of
heat-loss calculations from Table 8.

TABLE 8 Estimated Ratio of Collector Area to Floor Area, g =

h (65 − t )/i for 36 to 48° North latitude *
o
L
τ

Table 8 lists ranges of the estimated ratio of collector area to floor area, g,
of a space for latitudes 36°N or 48°N based on 4°F (2.2°C) intervals of
average January temperature and on various types of passive solar collectors.

Average January temperatures can be selected from government weather
data. Denver has an average January temperature of 32°F (0°C). Choosing a
direct-gain system for this installation, read down to the horizontal line for t o

= 32°F (0°C), and then read right to the column for a direct-gain system. To
find the estimated ratio of collector area to floor area, use a linear
interpolation. Thus for Denver, which is located at approximately 40°N,
interpolate between 48°N and 36°N values. Or, (0.24 − 0.20)/12 × (40 − 36)