Retrotec USACE User Manual
Page 433
Appendix N N3
TABLE N1. MINIMUM DATA SET FROM BUILDING EQ
Item
Measured value
unit
time
resolution*
remarks
consumption
total consumption of natural gas
kWh
h
natural gas
Total consumption of fuel oil
kWh
h
Fuel oil
total consumption of district heat
kWh
h
total consumption of district cold
kWh
h
total consumption of electricity
kWh
h
total consumption of water
m³
h
weather
outdoor air temperature
°C
h
own weather station or from weather data provider
outdoor rel. humidity
%
h
own weather station or from weather data provider
global irradiation
W/m²
h
own weather station or from weather data provider
Indoor conditions
indoor temperature
°C
h
choose one or more reference zones for that measurement
indoor relative humidity
°C
h
choose one or more reference zones for that measurement
System
Flow / return Temperatures of
main water circuits
°C
h
main heat/cold distribution.
”Main” in this context refers to the distribution in the building
and not to a primary distribution such as a district heating system.
supply air temperature of main
AHUs
°C
h
only if supply air is thermodynamically treated
supply air relative humidity of
main AHUs
%
h
only if supply air is humidifi ed / dehumidifi ed
* h = hourly
TABLE N2. DESIRABLE ACCURACY OF DATA POINTS
Measurement Point or Metric
Accuracy Goal
Outside ambient temperature (°F)
.2 °C
Outside ambient wet bulb temperature (°F)
.2 °C
Zone temperature (°F)
.5 °C
HVAC electric only energy use (kWh)
1.5% of reading
Chilled, hot water temperature (°F)
.1 °C, if >= 5 °C delta T
Chilled, hot water delta temperature (°F)
2% of reading
Chilled, hot water fl ow (gpm)
2% of reading, > 20–1 turndown
Natural gas fl ow (scfm)
2% of reading, > 10–1 turndown, w/ pressure and temperature compensation; Using an
average heat content of the gas to convert to kBtu introduces a –2% error
Air fl ow (cfm)*
5% of reading down to 10% of full scale, > 10–1 turndown
Power (kW)
2.0% of reading
Chiller cooling output (tons)
3% of reading
Chiller cooling energy (ton-hrs)
3% of reading
Boiler heating output (kBtu/hr)
3% of reading
Boiler heating energy (kBtu)
3% of reading
Electric energy use (kWh)
2.0% of reading
Total HVAC energy use (kWh) (inculdes air side, water
side and natural gas)
3% of reading
Chiller performance (kW/ton)
4% of reading
ChW Plant performance (kW/ton)
4% of reading
Total boiler performance (kBtuo/kBtui) (COP)
4% of reading
Total air handler performance (kW/cfm)
6% of reading
Net Usable Building fl oor area
2%