Page 70 - GRIHA Manual Volume III - Introduction to National Rating System
P. 70
Building and system design optimization 63
# Building envelope: Heat gains and losses occur through the entire exposed surface area of the
building. Thus, in case of air-conditioned buildings, use of insulation in roof and walls along
with high performance glazing assist in reducing the heat transfer to and from the surrounding
environment. This leads to reduction in the load on the HVAC system.
# Lighting (LPD reduction strategies): The lighting system design is considered as effective and
energy-efficient, if the visual comfort, as specified by NBC-2005 as well as the lighting power
density LPD (W/m ) requirements, as specified by ECBC-2007, are met.
2
# HVAC system optimization: Once the overall cooling/heating load of the building has been
reduced through interventions like appropriate shading, application of roof and wall insulation,
high performance glazing and LPD reduction, the final step is to optimize the HVAC system
required for meeting the cooling/heating load of the building. HVAC system optimization
includes the following.
1. Selection of appropriate system based on building cooling demand and building
operational hours.
2. Meeting the minimum requirement specified by ECBC while selecting HVAC equipment.
3. Meeting the minimum requirement specified by ECBC for integration of HVAC controls.
4. In addition to meeting the mandatory equipment and control specification requirements
of ECBC, HVAC system can be further optimized through several other energy-saving
strategies. Examples of these strategies include use of energy recovery wheels (for pre-
cooling of fresh air), use of chiller water reset control, use of chiller start and stop delay
control, and so on.
Following section provides details of some of the common types of air conditioning systems
1. Convective cooling/heating system
The convective cooling/heating system is further divided into the following two categories.
a. Unitary AC
b. Central AC system
Unitary AC
i. Window AC
Components: In window air-conditioners, the compressor, condenser, condenser fan,
and evaporator are all enclosed in a single cabinet. Window AC is installed either in
windows or designated voids can be left in the walls where the window units can be
installed.
Cooling capacity: 0.5–2.0 TR (tonnes of refrigeration).
Features: Window air-conditioners have a low initial cost. However, they have a higher
operating cost due to lower efficiencies. The primary reason for low-efficiency of window
air conditioners is dirty filters.
ii. Split air-conditioners
In split air-conditioners a separate indoor unit supplies cool air inside the room, while
outdoor unit removes the heat from the refrigerant.
Components: Split AC has two basic components—the indoor and outdoor units.
These two units are connected through refrigeration tubing and electric wires (that
# Building envelope: Heat gains and losses occur through the entire exposed surface area of the
building. Thus, in case of air-conditioned buildings, use of insulation in roof and walls along
with high performance glazing assist in reducing the heat transfer to and from the surrounding
environment. This leads to reduction in the load on the HVAC system.
# Lighting (LPD reduction strategies): The lighting system design is considered as effective and
energy-efficient, if the visual comfort, as specified by NBC-2005 as well as the lighting power
density LPD (W/m ) requirements, as specified by ECBC-2007, are met.
2
# HVAC system optimization: Once the overall cooling/heating load of the building has been
reduced through interventions like appropriate shading, application of roof and wall insulation,
high performance glazing and LPD reduction, the final step is to optimize the HVAC system
required for meeting the cooling/heating load of the building. HVAC system optimization
includes the following.
1. Selection of appropriate system based on building cooling demand and building
operational hours.
2. Meeting the minimum requirement specified by ECBC while selecting HVAC equipment.
3. Meeting the minimum requirement specified by ECBC for integration of HVAC controls.
4. In addition to meeting the mandatory equipment and control specification requirements
of ECBC, HVAC system can be further optimized through several other energy-saving
strategies. Examples of these strategies include use of energy recovery wheels (for pre-
cooling of fresh air), use of chiller water reset control, use of chiller start and stop delay
control, and so on.
Following section provides details of some of the common types of air conditioning systems
1. Convective cooling/heating system
The convective cooling/heating system is further divided into the following two categories.
a. Unitary AC
b. Central AC system
Unitary AC
i. Window AC
Components: In window air-conditioners, the compressor, condenser, condenser fan,
and evaporator are all enclosed in a single cabinet. Window AC is installed either in
windows or designated voids can be left in the walls where the window units can be
installed.
Cooling capacity: 0.5–2.0 TR (tonnes of refrigeration).
Features: Window air-conditioners have a low initial cost. However, they have a higher
operating cost due to lower efficiencies. The primary reason for low-efficiency of window
air conditioners is dirty filters.
ii. Split air-conditioners
In split air-conditioners a separate indoor unit supplies cool air inside the room, while
outdoor unit removes the heat from the refrigerant.
Components: Split AC has two basic components—the indoor and outdoor units.
These two units are connected through refrigeration tubing and electric wires (that
