GUIDANCE FOR PREPARATION OF COMPUTER ENERGY ANALYSIS
1. Computer Program Requirements. The computer energy analysis program shall
use technically recognized calculation methods to assure the credibility of
the program results. Energy consumption shall be calculated by an hourly load
and system simulation rather than the approximate degree day method. Computer
energy programs shall also meet the following requirements:
a. The heating and cooling load calculations and the heating and
cooling system simulation should be performed for each hour of the day for
twelve to 365 days in order to determine yearly energy consumption. When
annual calculations are made using less than 365 days, the weather data for
those days shall be statistically chosen in order to yield results
representative of the entire year.
b. The weather days must be taken from historical yearly weather data
tapes which are available from the Department of Commerce, National Climatic
Center, Ashville, North Carolina (704) 254-0961, extension 203.
c. The heating and cooling loads must take into account the thermal
time lag of building materials by such methods as thermal response factors or
the ASHRAE averaging method.
d. The heating and cooling loads must take into account the internal
loads generated by people, lighting, machines and other sources.
e. The internal loads, the ventilation rates and the thermostat
settings must be capable of being varied with the hours of the day and the
days of the year in order to simulate normal building operations.
f. The heating and cooling system simulations shall include the energy
requirements of the mechanical system components such as fans, pumps, chillers
g. Perform the energy life cycle cost analyses for any new building or
major renovation project that is heated only, or heated and/or air-conditioned
and exceeds 3,000 ft2 using a professionally recognized and proven computer
program that allows for the integration of architectural features and heating
and air conditioning systems to determine that such features and systems will
result in the lowest life cycle cost.
2. Building System Alternative. Professional judgment is essential to the
intelligent selection of building system alternatives. The first
consideration of a building system is that it satisfies all functional and
aesthetic requirements. Computer energy analysis programs allow evaluation of
a large number of practical building system alternatives to optimize energy
conservation and to achieve significant long range savings. The computer
energy analysis programs should be capable of analyzing all relevant
alternatives. Projects which require a consideration of total energy systems
must be analyzed by a program which is capable of total energy system