Climate surfaces: a quantitative building-specific representation of climates

Based on the power balance equation, an analytical tool for the calculation of the free-run-temperature of a room has been developed and a universally valid energy-strategy derived. The description of the thermal behavior of a room is traced back in this approach to three parameters only: the generalized loss-factor K, the time constant π and the gain-to-loss ratio γ. By an appropriate inclusion of solar gains the usual definition of ‘heating-degree-days’ is extended to ‘generalized heating-degree-days’, represented graphically as a function of π and γ. These two parameters yield the ‘climate surface’ of the room under consideration. A comparison with measured data from actual buildings confirms the validity of this approach. In order to illustrate its practical value, the method of climate-surfaces is applied in this paper to generate surfaces for design-temperature differences and to deduce optimized heating, cooling and control strategies, as well as strategies for the night set back solar shading, night cooling etc.