CIRA: A Microcomputer-Based Energy Analysis and Auditing Tool for Residential Applications

摘要

Computerized, Instrumented, Residential Audit (CIRA) is a collection of programs for energy analysis and energy auditing of residential buildings. CIRA is written for microcomputers with a CP/M operating system and 64K RAM. Its principal features are: user-friendliness, dynamic defaults, file-oriented structure, design energy analysis capability, economic optimization of retrofits, graphic and tabular output to screen and printer. To calculate monthly energy consumptions both for design and retrofit analyses CIRA uses a modified degree-day and degree-night approach, taking into account solar gains, IR losses to the sky, internal gains and ground heat transfer; the concept of solar storage factor addresses the delayed effect of daytime solar gains while the concept of effective thermal mass ensures proper handling of changes in thermostat setting from day to night; aie infiltration is modeled using the LBL infiltration model based on effective leakage area; HVAC system performance is modeled using correlations developed for DOE-2.1. For any given budget, CIRA can also develop an optimally sequenced list of retrofits with the highest combined savings. Long run-times necessary for economic optimization of retrofits are greatly reduced by using a method based on partial derivatives of energy consumption with respect to principal building parameters. Energy calculations of CIRA compare well with those of DOE-2.1 and with measured energy consumptions from a sample of monitored houses. (ERA citation 08:026551)