BO-2363 -- Comparison between Measured Computer-Predicted Hourly Heating and Cooling Energy Requirements for an Instrumented Wood-Framed Townhouse Subjected to Lab Tests ✓ Most Recent

With the advent of high speed computers with large memory banks, it has become possible to calculate hourly heating and cooling loads for a building as affected by fluctuating outdoor weather conditions, changing solar radiation intensities, and varying internal heat generation to a high degree of sophistication. A set of algorithms (1) has been developed by the ASHRAE Task Group on Energy Requirements for calculating hourly heating and cooling loads. They were prepared with the assistance of the National Bureau of Standards and the National Research Council of Canada.

The National Bureau of Standards Load Determination Program (NBSLD) (2) is a group of routines utilizing the ASHRAE algorithms that calculates either time-varying heating and cooling loads or variations of indoor temperature. The use of NBSLD virtually eliminates the possibility of missing the maximum load of a building and makes it possible to select the size of heating and cooling equipment to match the building heating and cooling loads. In using this computer program, it is necessary to provide as input outdoor weather conditions, the construction details of the building (such as a layer-by-layer description and the heat transfer areas of its exterior surface components, its orientation, etc.), and the building operating schedule for equipment, lighting, and occupancy. The algorithms of the computer program then operate on this input data in such a manner as to predict either inside air temperature or heating and cooling loads.