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Description:
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Typical energy audits are sufficiently expensive and time -consuming that many
owners and managers of buildings are not willing to invest the time and money required
for a full audit . This dissertation provides a methodology to identify buildings with large
potential energy savings using limited information , specifically , utility bills , total area
and weather data . The methodology is developed based on the hypothesis : if a
commercial building is properly designed , constructed , operated , and maintained , the
measured energy consumption should approximately match the simulated value for a
typical building of the same size with the most efficient HVAC system ; otherwise , there
may be potential for energy savings . There are four steps in the methodology : 1 ) testing
to determine whether the utility bills include both weather -dependent and weatherindependent
loads ; 2 ) separating weather -dependent and weather -independent loads
when both are present in the same data ; 3 ) determining the main type of HVAC system ;
4 ) estimating potential energy savings and recommending an energy audit if appropriate .
The Flatness Index is selected to test whether the utility bills include both weatherdependent
and weather -independent loads . An approach to separate the utility bills based
on thermal balance is developed to separate utility bills into weather -dependent and
weather -independent loads for facilities in hot and humid climates . The average relative
error in estimated cooling consumption is only 1 .1 % for 40 buildings in Texas , whereas it is -54 .8 % using the traditional 3P method . An application of fuzzy logic is used to
identify the main type of HVAC system in buildings from their 12 -month weatherdependent
energy consumption . When 40 buildings were tested , 18 systems were
identified correctly , seven were incorrect and the HVAC system type cannot be identified
in 15 cases . The estimated potential savings by the screening methodology in eight large
commercial buildings were compared with audit estimated savings for the same
buildings . The audit estimated savings are between 25 % - 150 % of the potential energy
savings estimated by the screening procedure in seven cases . The other two cases are less
accurate , indicating that further refinement of the method would be valuable . The data
required are easily obtained ; the procedure can be carried out automatically , so no
experience is required . If the actual type of HVAC system , measured weather -dependent ,
and weather -independent energy consumption are known , the methodology should work
better . |