Structural Design of the mCCHP-RES System - Design for Micro-Combined Cooling, Heating and Power Systems - page 174

Table 13 Steps in building heat loss coef cient
Step 1: envelope heat transfer coef cient (UA conduction)
Building element U-value Area U × area Description

kW/ m 2 C 2 Orientation Element ° kW/ ° C

South Walls
Window
East Walls
Window
North Walls
Window
West Walls
Window
Ceiling/roof
UA envelope kW = ð Þ U A kW = ð Þ
Step 2: In ltration heat loss ( “ UA ” in ltration)
Volumetric heat capacity (air) kWh/m 3 ° C

m 3 Building volume

Air changes per hour (ACH) 1/h

UA in ltration = VHC × Volume × ACH [kW/ ° C]

Step 3: perimeter heat loss ( perimeter)

Heat loss coef cient (F) kW /m ° C
Length of building perimeter (P) [m]
UA perimeter = F

“ UA ”

× P kW/ ° C

UAref ' kW/ ° C

The steps in building heat loss coef cient (UA) are shown in Table 13 .

B. Finding the measured overall heat transfer coef cient of the building

Thermographic survey techniques, based on infrared cameras, are not a recent
development and are

rating. There are really two essential elements
for achieving a good infrared audit, namely, the high performance instrument and
the technical skill of the infrared auditor. Analysis is very useful for evaluating the
building

“ operational ”

s energy performance, both for its envelope and its facilities. In fact it
could lead to identi

'

final design,
construction, installation, or building malfunctions. For example, the knowledge of
energy performance of existing buildings could render feasible their respective
retro

cation of many energy problems such as bad

tting activities, while in new buildings it is possible to check the accuracy of

the construction compared to the project details. It is also used to verify

the presence of air seepage, moisture, or water leaks.
In order to correctly de

“ as-built ”

ne the performance of a building envelope, it is very important
to know, in addition to the characteristics of the building materials, the re ected ambient