CNC Report 08.26.24 8.5x11 - Flipbook - Page 40
OPTIMIZE ALL-ELECTRIC SYSTEMS WITH
ON-SITE RENEWABLE ENERGY GENERATION
After passive strategies have been designed, what is the best approach for system efficiency and
optimization?
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Transition to efficient water-based heating/cooling systems and heat pumps (good combination
with PV for cooling during summer).
Use a dedicated outdoor air system (DOAS) systems to provide minimum outside air for office
and retail spaces in addition to radiant heating and cooling.
Distribute air from below (displacement ventilation) to ensure healthy fresh air levels indoors.
Eliminate variable refrigerant flow (VRF) systems that have high leakage rates (high global
warming potential of refrigerants).
1. Heat Pumps and Geothermal Systems
The use of heat pumps for heating/cooling can significantly reduce a building’s Energy Use
Intensity(EUI) and operational carbon emissions.
• Heat pumps harness the heat from the environment (air, ground, groundwater, etc.) and the
properties of a refrigerant to efficiently provide hot or chilled water.
• Typical heat pumps for space heating (e.g. low temperature radiant floor systems) turn 1 part
electricity into 5 parts heat (from the environment), hence their coefficient of performance (COP)
is 5.
• Types of usable environmental heat:
• Air: less efficient as temperature fluctuates strongly over the year, lower capital cost.
• Geothermal (ground + groundwater): efficient, as temperature is typically very constant
(caution with imbalanced loads: ground can heat up or cool down too much when there is an
imbalance in heating or cooling over the year).
• closed loop: requires least maintenance, highest capital cost
• open loop: high maintenance but each well is higher capacity so less capital cost
• horizontal: lower capacity and lower capital cost
• Consider the use of geothermal fields as the heat source/sink for heat pumps (more efficient than
air as source/sink). Geothermal could be implemented below parking lots or other unused open
areas where drilling boreholes is easier.
2. Maximize PV Renewable Energy Generation
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Design buildings to optimize surface area with high solar radiation for PV including on rooftops,
carports, or overhangs.
PV arrays generate clean electricity through the photo-voltaic effect in which voltage (and thus
electric current) is generated in the PV cells when exposed to sunlight.
A large driver of overall carbon emissions is due to the operational energy of buildings and
electricity usage due to a “dirty” grid (burning of fossil fuels still contribute a large proportion of
its generation). To avoid the carbon emitted, renewable energy generation should have maximum
coverage over the site where possible. This includes building rooftops, over parking structures, on
West facades, and as PV canopies over the streetscape and along the road.
archimania
Transsolar
KlimaEngineering
