HVAC Energy Efficiency
Ventilation, indoor air & heating installations
HVAC adjustments and implementation
The sole responsibility for the content of this publication lies with the authors. It does not necessarily
reflect the opinion of the European Union. Neither the EASME nor the European Commission are
responsible for any use that may be made of the information contained therein.
Energy efficiency of technical
installations is influenced by:
• The choice of the appliance, systems and their
consistencies
• The routes and insulation of the ducts and pipes
• Compactness of ducts, through-holes and rooms
• The purity of louvres, filters and valves
• Fine-tuning the system and automation control
• Use and maintenance
Ventilation and indoor air
The sole responsibility for the content of this publication lies with the authors. It does not necessarily
reflect the opinion of the European Union. Neither the EASME nor the European Commission are
responsible for any use that may be made of the information contained therein.
Ventilation
• Ventilation is one of the most significant parts of a building’s
energy consumption.
• Ventilation brings fresh air from outside to inside. Impurities are
then removed from the inside air.
• Impurities:
• Carbon dioxide, moisture, dust, toxins, allergens, smoke from kitchen
• Discharges from building materials and furniture.
• Deficient ventilation causes:
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Stuffiness, smells
Increased carbon dioxide - headache and exhaustion
Moisture condensation – moisture damage
Favourable habitat for microbes
• The air must move freely between different rooms
• Remember threshold gaps, keep doors open,…
Good quality indoor air
• good supply of fresh air
• the recommended temperature of the
room is 20-22o C; under 18o C and over
23o C can cause health problems
• air flow in the rooms, according to rules,
is 0.2 m/s, recommended is 0.1 m/s
• good indoor air has less than 900 ppm of
co2 (co2 is a good indicator of air quality)
• the picture shows an indicator used to
measure air quality
Amount of ventilation
• All the air is changed every 2 hours. (ventilation rate 0.5 1/h).
• In an empty building at least 0.2 times in an hour.
• Fresh air per person is 6 litres per second meaning 21m3/h
(adjustment if necessary)
• Fresh outside air is brought to bedrooms and living rooms.
• Bedroom 0.5 l/s/m2
• Living room e 0.5 l/s/m2.
• The air is removed from the rooms with a lot of moisture or
impurities.
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kitchen 8 - 25 l/s
bathroom 10-15 l/s
utility room 8-15 l/s
toilet 7-10 l/s
sauna 2 l/s/m2
walk-in closet, stores 3 l/s.
Natural ventilation
In natural ventilation, the warm air goes out
through the flue and fresh air is brought in
through valves on the walls.
Natural ventilation
• Common until the 1960s
• Natural ventilation is based on lighter warm air rising. The differential pressure
is created between indoor and outdoor air because of temperature differences.
• In the winter, the temperature difference between indoor and outdoor air is
huge, so the differential pressure is also huge so ventilation is working well.
• In warm seasons, for example, oil heating warms the flue and encourages
natural ventilation. (Usually, a brick flue is the exhaust route for the air)
• A good supply of air has to be ensured (ventilators, window ventilators)
• Keeping carbon dioxide at the target level usually requires constant airing
(windows).
• Closing a ventilator because of draught is a common problem.
• Regular cleaning of ventilators is a general overhaul.
Example of 150 m2 house with natural
ventilation
Air quality:
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Supply air downstairs:
• 3 ventilators
• 1 ventilation window
ajar (1cm)
Exhaust air:
• Downstairs bathroom 1
exhaust air ventilator
• Upstairs bedrooms the window
is ajar and one exhaust air
ventilator is over the window
Outdoor temperature -25o C
Two persons on both floors.
The carbon dioxide rate
upstairs stays acceptable in
the bedrooms
Mechanical extraction
• Common in the 1960-1990’s
• Air is removed by fan
• Adjustment usually by the
cooker hood
• Requires sufficient fresh air
and transfer air routes
• Closing the valves because of
draught is a common problem
• The action of the fans must be
controlled
• The valves must be cleaned
regularly
Mechanical extraction
Fan
Bedroom
Outdoor
air
Transferred
air
Living room
Bathroom
Exhaust
air
Kitchen
Picture: Sisäilmayhdistys
Mechanical input and extraction
ventilation
• The air is brought in and removed
by fans.
• Accurate adjustment; the weather
does not affect ventilation.
• The supply air is filtered and preheated if needed.
• By heat recovery, the energy of
exhaust air can be brought back
to the building.
• The building is usually designed
0-10 Pa below the pressure of the
outdoor air so moisture damage
in the structures can be avoided.
The envelope of the building must
be absolutely tight.
• In old buildings, low pressure can
absorb microbes in the indoor air.
Mechanical input and extract ventilation
Air supply unit,
heat recovery
Fan
Bedroom
Bath
room
Cooker
hood
Fire place switch
Living room
Kitchen
Outdoor air
Supply air (heated)
Transferred
air
Exhaust air
Picture: Sisäilmayhdistys
Outdoor
air
Heat recovery
• A significant part of heating energy from exhaust air can be recovered
by heat exchangers.
• The supply air is heated by the heat content of the exhaust air or the
heat is transferred to the drinking water by the exhaust air heating
pump.
• The use of heat recovery requires buildings to be tight.
• The efficiency of a modern heat recovery appliance is approx. 80%.
Example
Bridging sheet
-5
Fresh air
Exhaust air
+22
Bridging sheet
+12
Extract air
Supply air
+13
Heating
The sole responsibility for the content of this publication lies with the authors. It does not necessarily
reflect the opinion of the European Union. Neither the EASME nor the European Commission are
responsible for any use that may be made of the information contained therein.
Heat production methods
Renewable energy and hybrid systems are becoming more
common
Air source heat pumps ASHP
• In Finland, about 500,000 ASHPs were installed before 2014
producing 5 TWh of energy per year. By 2020, an additional
500,000 air heat pumps are estimated to be installed.
• Residential buildings use 200,000 boilers, 100,000 other water
circulation heating systems and 500,000 electric heating systems.
Air heat pumps are also very suitable and can even replace existing
pumps.
• There are 36,000 exhaust air systems in apartment buildings. An
exhaust air heat pump is a good energy-saving device in apartment
buildings. It can reduce energy costs by 40-50%.
• The energy company can not increase the price of energy just
because there is an air source heat pump in the apartment building.
• The compressors of the air heat pumps are reliable but the failures
of the installation, adjustment or use can reduce the benefits of the
air heat pump.
• Users need clear written instructions and personal guidance on their
use.
Features of ASHPs
• The efficiency COP of ASHPs indicates how efficiently used electric energy can be
changed to heating energy. COP value is measured always in temperature of +7 degrees.
For example, number 4 means that one kilowatt of the electricity taken from the grid has
produced 4 kilowatt of heating power.
• The coefficient of performance of the heating period, SCOP, is calculated for four different
kind of heating. Europe has been divided into three different climatic zones. The
northernmost zone is based on the climate of Helsinki. That value is not always presented
in the brochures of the ASHP.
• EER means the cooling efficiency factor. A good EER value is over 3.5.
• SEER means a yearly cooling efficiency factor. Usually that is not a very substantial
criterion in Finland.
• A Swedish survey demonstrated that the SCOP values of the geothermal heat pumps in
the 2010’s in floor-heated houses were 3.5-5 and in radiator heated-houses 3.0-4.
• The SCOP values of the air/water heat pumps in southern Sweden were 1.8-3.0 in
radiator- heated houses and the SCOP values of the air heat pumps were 2.8-3.4
(average temperature 6.1o C)
• In northern Sweden the SCOP values of the ASHPs were 1.7-2.6 (average temperature
+1.3o C)
Comparing and choosing an ASHP
• ASHPs are suitable as the primary heating method in new
buildings and as an secondary heat source in old buildings.
• When choosing an ASHP consider:
• SCOP, climate and purchase price.
• The existing heat distribution method: an old one with a sheet
radiator does not achieved the best efficiency of an air/water
heat pump or a geothermal heat pump. A lower floor
temperature raises the efficiency of pumps.
• The indoor air can be cleaned and the temperature of the room
can be adjusted fast and flexibly with an ASHP. But the interior
requires regular cleaning.
• With floor heating, the air/water heat pump and the geothermal
heat pump give comfort and ease of use.
Hybrid systems
A hybrid system means a common use of heat production methods. Heat air
pumps are usually used with hybrid systems.
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In hybrid systems the energy is first taken from the heat air pump and when
the capacity of the heat pump is reached, heat is taken from other sources.
•
Usually a slightly smaller (part power heat pump design) is the most
economical. At the coldest time the fireplace or electric heating is also used.
This also saves the depth of the bore well of the geothermal heat pump.
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Hankinnan yhteydessä tulee eri mitoitusvaihtoehtoja vertailla ja varmistaa,
että tarjousten mitoitukset ovat vertailukelpoisia.
•
The inner unit of the ASHP is installed in the room. It should be as big and
clear as possible and.
• Other heaters must be adjusted to the lowest temperature in the area covered
by the inner unit.
• In the room where the air heat pump is situated, the temperature is adjusted to
a higher limit than the other rooms. Then the warm air is eddied to the other
rooms.
• Optimising the use of three different heat sources is difficult.
• Proper adjustment must be tested in both the cold and the warm season.
Solar heating since 1985
There is a huge variation in
temperatures of solar collectors
→ thermal radiation in the
fasteners, junctions and
penetration
→ thermal radiation in the pipes
→ boiling and evaporating of the
liquid
→ danger of over heating and
fire
→ Insulation and sealing
Heat distribution
• The pre-set control of heat distribution must take into consideration that the
rooms in the corners of the building and the lower floors need more heating.
Also heat loads like solar radiation and the delays based on the charging
capacity of the structures need to be considered.
• In low-energy houses, the variation of inner heat loads has a quick and
significant effect on heat demand. Variations in outdoor temperatures have a
slow and minor effect on heat demand.
• Radiator heating is easy to adjust, but requires
relatively hot water.
• The low temperature of floor heating feels nice but
means high heating power. Slow control can cause
over heating.
• Insulating heat pipes and the pipes of warm circulation water is important
because of heat loss and heat loads.
• Temperature, comfort, air flows and draught must also be taken into account.
• To eliminating draughts and ”cold radiation”, the heating can be adjusted to a
lower temperature.
• Reducing the temperature 1o C reduces the need for heating by 5%.
HVAC Installation
The sole responsibility for the content of this publication lies with the authors. It does not necessarily
reflect the opinion of the European Union. Neither the EASME nor the European Commission are
responsible for any use that may be made of the information contained therein.
Installation routes
When installing ducts and pipes consider:
• Making sizes of ducts and reductions
according to the plans
• Minimizing pressure losses by avoiding
unnecessary corners and bends.
• Allowing enough space for duct and pipe
insulation and other installations
• Ventilation ducts, HEVAC-pipes, cable trays,
insulations, luminaires
• Pumps, dampers, sound traps,
• Indicators, thermostats, sensors,…
Installation routes must be agreed
• Cooperation with all service installers on site is essential.
• The principles for layout, at least of corridors and flues, must be
agreed beforehand. Places for insulation must also be marked.
• Cooperation with designers is also important. For example, ask
designers for the cross-sections of the corridors near heat
distribution rooms and ventilation plant rooms.
Installing and insulating roofs
• Insulate supply air ducts properly in cold spaces.
• Confirm that settling of insulation under the ducts will not cause a cold air
hollow.
• Fit wool mats, for example, between the trusses, the disposition of ducts near
the truss and loose-fill insulation above. Make loose-fill insulation compact if
needed.
• If possible, install the warm pipes on the warm side of insulation and the cold
pipes to the cold side of insulation.
• Condensate insulation is needed, for example, with:
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Supply air ducts in warm spaces
Stack vents in warm spaces
Cold running water in warm spaces
Insulation of return air ducts in cold spaces
• Make through-holes in the envelope
very properly together with structural
work.
Duct insulation
• Joints are overlapped using multi
layered insulation.
• Transverse seams are positioned
where the fasteners are.
• Longitudinal seams always face
downwards if possible.
• Insulation joints with aluminium
surfaces are always taped with
aluminium tape.
• The resistance of the insulation is
ensured by taping steel wire
around the pipe with a 250 mmgap between the bonds.
The appropriate use of electricity
Choose electric appliances and systems which can be controlled
appropriately.
• The running power of the ASHPs and the ventilation
units can be reduced when the house is empty..
• The temperature can be reduced at night.
• The floor heating can be controlled by a thermostat and a
timer switch
when the heating is needed less
• Laundering and washing-up can be programmed to be done at night when
electricity consumption is low. It will reduce the bill from the energy company
and can affect the pricing of electricity.
• Nowadays the consumer can buy electricity on an hourly tariff.
• Using a timer switch to pre-heat cars and to charge electric cars
according to outdoor temperature and during the off-peak tariff time
• Adjusting the lighting in rooms and outdoors with a timer switch, by the pecu
switch and motion detectors. The start values set energy efficiently but consider the need for
lighting
• The heating of electric sauna stoves and hot-water tanks can be rotated with the heating of the
rooms by an electricity load control system
• The appliances with A+++ are recommended.
Fine-tuning and commissioning HVAC
The sole responsibility for the content of this publication lies with the authors. It does not necessarily
reflect the opinion of the European Union. Neither the EASME nor the European Commission are
responsible for any use that may be made of the information contained therein.
Energy efficiency of building automation
installations
• In the installations of thermostats and sensors must be
noticed the cooling or warming effects of other devices and
systems like solar radiation, supply air, cool surfaces
• The controlling apparatus of the appliances are clearly
named. For example time switches are named in words, not
with codes.
• Outside the switchboard door is marked the info of the
switches and inside the room the instructions of the
switches are stored.
• The controls are set case-specific and appropriate with the
users .
• The heating and ventilation can be controlled apart from
time switches and temperature sensors with moisture and
carbon dioxide sensors, move detectors and by measuring
the sunlight.
• The appropriate control of heating can reduce the need for
heating energy and even improve the heat comfort – The
places where people stay are heated.
Commissioning the HVAC
• Before commissioning the building, the HVAC systems
must be tested and adjusted with the help of functional
tests.
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adjustment of the air amount
pre-adjustment of the radiator ventilators
the operation of thermostats and sensors
the measurement of temperatures
the survey of the effects of heat load
AC-engine
room in Ideapark
testing the cooperation of the systems
the copies of functional diagrams and field books are left in
the engine room and in the heat distribution room
• ensuring the operation of the control, alarm and report
systems
• the users of the systems are guided to use the systems
properly
• There must be enough time for functional tests.
• The rooms must be able to close (the doors shut), so
Heat exchanger
the measurements are reliable.
• During the functional test can not be done any building
works anymore.
Synchronizing the systems
• The heating and cooling should not be used at the same
time. Fading between heating and cooling must be
prevented: allow enough time between.
• Thermostats and sensors must be installed in places where
there is no extra heat load or cooling.
• Notice:
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ventilation air supply
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external heat loads e.g. solar radiation
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lights
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the blast from the appliances.
Thermostats should not be
covered by fittings, curtains, towels, etc.
Remember
• Tight structures and through-holes and proper insulated
installations are the basis for an energy-efficient HVAC.
• The design and adjustment of hybrid systems is challenging.
Testing is important.
• The operating system must control:
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Quality, warmth and moisture of the air
Carbon dioxide, volume of air and air flow
Energy consumption
Maintenance e.g. cleaning the ventilation filters.
• How people use the system has a major effect on energy
consumption. Users must learn how to use the system.
• There are many ways of reducing energy consumption
which may even increase the comfort of the building.
The good practices and principles required for the energy efficient building have been
included in the teaching material. The writers are not responsible for their suitability to
individual building projects as such. The individual building projects have to be made
according to the building design of the targets in question.