Project Green District Energy Feasibility Study - Partners in Project ...

TRCA Pearson Eco-Business Zone District Energy Feasibility Study 10 April 2012
Appendices
DES – District Energy System means a system to supply heating and/or cooling to multiple
buildings.
Diversified Peak Demand – the sum of the peak thermal demands (i.e. heating or cooling) of
all buildings served by a DES multiplied by a factor to reflect the fact that different buildings’
peak demands are not coincident. For district heating, a factor of 0.8 to 0.85 has been found to
be appropriate.
Degree Days – a measure of how hot or cold a location has been within a stated period of time,
relative to a reference temperature; Heating Degree Days (HDD) may be quoted below 15°C,
and Cooling Degree Days above 15°C, if that happens to be the outside air temperature below
which heating is generally turned on and above which cooling is turned on.
DE – District Energy
DEC - District Energy Centre – a central facility where heating and/or cooling and/or electricity
are generated; a recently more preferred term to “energy plant” or “central plant”.
DPS - Distribution piping system for heating and/or cooling. This system consists of supply and
return pipes (of the same diameter) together with all necessary valves, vents, drains and fittings.
The pipes are usually buried underground, insulated for heating and situated between the
energy source(s) and customer buildings. Supply and return branches for each customer
building join the inside piping that connects the DPS to the building energy transfer station
(ETS) (see below).
DHW – domestic hot water; district heating systems usually supply DHW along with space
heating and it accounts for most of the summer load.
ΔT – delta T – difference in temperature, e.g. as between the supply and return lines of a district
heating or district cooling loop.
Energy Centre - A central facility where heating, cooling and/or electricity is generated. This is
a preferable term to “energy plant” or “central plant”
EFLH - Equivalent Full Load Hours, annual energy consumption divided by peak load. Heating
EFLH for a building is a function of the local annual outside air temperature profile, the outside
air temperature when heating is turned on, domestic hot water consumption and any other nonspace
heating uses of heat. Cooling EFLH is a function of the local annual outside air
temperature profile, the outside air temperature when cooling is turned on, humidity (it takes
cooling energy to de-humidify) and any other non-space air-conditioning uses of cooling.
ETS - energy transfer stations. They are in each customer building and consist of heat
exchangers, energy meters, controls, valves and inside piping.
Heat Pump – a machine (very similar to a chiller) used for generating heat from energy sources
that are too low in temperature to be useful directly.
GJ – Giga-Joule, a billion Joules, a unit of heat commonly used in the natural gas industry in
Canada.
HVAC – heating, ventilation and air conditioning; the acronym is an indicator that these
functions must be viewed holistically.
kJ – kilo-Joule, a thousand Joules, 1 kJ per second = 1 kW
kWe – kilo-Watts of electricity
kWt - kilo-Watts thermal, heat or cooling, depending on context
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