HVAC System
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An HVAC system type must be selected from the list.
All the included rooms within the currently selected zone are assumed to be
served by the system type. The
HVAC System Type shows a list of standard
HVAC system types. Selecting one of these HVAC systems will automatically set
up the appropriate HVAC data.
The
Include Zone check includes the selected
zone and enables several controls in Heating System and in System Adjustments.
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Heating System
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You need to specify the Heating system heat source,
which defines how heating is supplied to the HVAC system. In addition, the fuel
type is selected for the heating system. The remaining data items are used to
determine the efficiency of the heat generator (boiler). The required data is:
- Seasonal
efficiency – If the efficiency is known, this should be entered
directly, if not, the remaining data items are used to infer the efficiency.
- Generator
radiant efficiency – If the efficiency is known, this should be
entered directly, if not, the remaining data items are used to infer the
efficiency. If the HVAC system is a Radiant heater, then you can specify a
Generator radiant efficiency if it is known, if not, the efficiency will be
assumed based on whether the heating is on the Enhanced Capital Allowance (ECA)
list.
- On ECA
list – defines whether the boiler is on the Enhanced Capital
Allowance (ECA) list. If not, you define whether the boiler was installed after
1998.
- Installed
on or after 1998- The heat generator seasonal efficiency can be
manually defined on the interface. For boilers installed after 1998 the
efficiency of 0.81 is suggested for boilers installed before 1998 the
efficiency of 0.65 is suggested .
- System uses CHP –
this enables CHP generator data to be defined for the zone on the General tab.
The
Bi-Valent systems section allows a bivalent
heating system to be setup. This is when the heating is supplied by two or more
different types of heat sources.
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Cooling System
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If the HVAC system requires cooling, then you must
specify a Cooling system packaged chiller type and the Chiller rating.
If the chiller seasonal efficiencies (Seasonal EER
and Nominal EER) are known, they should be entered, if not, the efficiencies
will be assumed based on whether the chiller is on the Enhanced Capital
Allowance (ECA) list.
Mixed mode operation strategy – if the HVAC system
has mixed mode operation strategy.
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System Adjustments
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The following system adjustments can be applied.
- Ductwork
leakage – if the system has been leakage tested, the CEN
classification (e.g. Class A) can be selected.
- AHU
leakage – if the AHU meets CEN leakage standards, the relevant
standard (e.g. L1, L2) can be selected.
- Specific
fan power – if the specific fan power (SFP) is known, it can be
defined, otherwise a default value will be used.
- Auxiliary
energy
– if the HVAC system is a Flued/Non-flued forced
convection air heater and the auxiliary energy of fanned warm air heaters is
known, it can be defined, otherwise a default will be used.
Variable speed pump – If
specified, HVAC system is one where variable speed pumping can be used these
options become available.
- Type of pump.
- Type of variable
speed control.
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Heat Recovery, Controls and Metering
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Zone based heat recovery –
Heat recovery for the HVAC system can be set up. Depending on the type of HVAC
system heat recovery is either specified at the zone level or the room level.
- Heat recovery –
depending on the HVAC system specified, heat recovery can be defined by
selecting the type of heat recovery.
- Seasonal efficiency
– if a heat recovery system is selected and the seasonal efficiency is known,
it can be defined, otherwise a default value will be used.
Metering provision – The
effect of system controls can be considered as follows. These are not available
if Type of analysis is set to Scottish Building Regulations.
- Metering – metering
should be included if there is energy metering of plant and/or metering of
plant hours run and/or monitoring of internal room temperatures.
- Out of range values
– you can specify whether the metering warns of out of range values.
Heating system controls –
Various heating system controls are available if Type of analysis is set to an
EPC calculation. These will trigger certain recommendations from being omitted
from the recommendations report automatically. The following options can be
selected:
- Central time
control
- Optimum start/stop
control
- Local time control
(ie., room by room)
- Local temperature
control (i.e., room by room)
- Weather
compensation control
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