Building Utilities 2: Midterms Reviewer part 2 Flashcards
Systems that remove heat from buildings
COOLING SYSTEMS
_ ___ _ ______ warm air is carried away from rooms to an air-
conditioning unit (ACU)
To cool a building
removes dust and other impurities
Air filter
contains a refrigerant that absorbs heat from the air passing around it
Cooling coil
pulls the warm air from the room & Pushes cooled air back to the rooms
Blower
Size of ACU or air-conditioning equipment –
rated in BTUs
Air cooling systems are designed to control:
Temperature and Humidity
Cooling Units that share blowers, ducts and outlets with heating systems
COMBINED HEATING AND COOLING SYSTEMS
Work like a reversible refrigeration system; Can both cool and heat buildings
HEAT PUMPS
________– a heat pump removes heat from indoor air through a closed refrigerant cycle
In warm weather
________-heat is drawn from the outside air, water or ground and transferred inside
In cold weather
Effective in warm or mild climates; Do not heat efficiently when temperatures are below 30°F (-1°C)
Air-source heat pumps
These are water-source heat pumps; Extract heat from the earth; More effective for heating in cooler climates
Ground-source (geothermal)
Two types of Ground-source (geothermal)
Open-loop system
Closed-loop system
Heat pump systems consists of:
▪ Inside air handler
▪ Outside heat pump
▪ Ducts
▪ Outlets
It pumps heat from the various rooms into a heat sink
Refrigeration machine
source of heat can usually be the outdoor air, but can be a body of water or the ground
Heat sink
What to use in small buildings,
condenser coil
What to use in medium buildings,
evaporator condenser
What to use in large buildings,
cooling towers
Air is blown across the cold evaporator coil and delivered by ducts to the rooms that require cooling; Effectively ventilate, filtrate and dehumidify air
All-Air Systems
Water is chilled by the evaporator coil and then delivered to fan-coil units in each space
All-Water Systems
▪ Bulk of cooling is handles by the water and fan-coil units
▪ Small air system completes the cooling
▪ Ventilates, dehumidifies and filter the air
▪ Most of the cooling is accomplished by the water systems
▪ Air ducts can be quite small
Combination Air-Water Systems
It is necessary to keep fresh air circulating
Ventilation
State when moisture is controlled and keeps air relatively dry
Effective ventilation
circulate air in attics, crawl spaces and
bathrooms
Ceiling and exhaust fans
Part of the house that remove excessive moist air
Crawl space ventilation
Part of the house that provide space for adequate circulation
High ceilings
VOCs
volatile organic compounds
filters filled with fiberglass or charcoal – remove 15% of all
pollutants
Mechanical filters
filters with ionizing wires – trap 99%
Electrostatic filters
– introduce low levels of ozone (electronically charged
oxygen) into the air supply
Ozonators
Thermostatic controls keep buildings at a constant temperature
TEMPERATURE CONTROL
sensing devices, located on interior walls away from sources of
heat or cold such as fireplaces or windows
Thermostats
is moisture in the air
Humidity
sensing devices that monitor humidity levels
Humidistats
Involves using the sun’s energy by integrating the systems with the basic
design of structure;
Operate without the use of mechanical or electronic devices to heat or cool
a structure
PASSIVE SOLAR SYSTEMS
any material that will absorb heat from the sun and later radiate the heat back into the air
Thermal mass
Heated air will always rise by convection until trapped
▪ Heating – re-circulate heated air from high places to cooler
lower areas
▪ Cooling – expel high level warm air
Rising Warm Air
▪ Ceiling heights
● Low – trap warm air in the living space
● High – allow warm air to rise
Remember
Passive Solar Methods:
Direct-Gain Method and Indirect-Gain Method
the inside of the building is heated by the sun’s
rays directly as they pass through large glass areas or structural
materials
Direct-Gain Method
– uses a thermal mass placed between the sun
and the inside of a building
Indirect-Gain Method
✔ Use mechanical devices to drive the components needed for solar heating
or cooling
✔ Operate more effectively when combined with passive solar features
ACTIVE SOLAR SYSTEMS
needed for
cloudy periods
Backup Power
These should be set at an angle perpendicular to the rays of the sun for maximum collection per day or use rotating collectors
Heat collectors
ASHRAE
American Society of Heating, Refrigerating and Air-Conditioning Engineers
INDUSTRY STANDARDS
(ASHRAE, 2020)
Residential ventilation standards
– to make houses healthier for the
occupants
- exhausting pollutants from a point close to
the source (bath and kitchen fans)
Local ventilation
