HVAC - PowerPoint Presentation

Slide1

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.Slide2

Energy efficiency of technical installations is influenced by:The choice of the appliance, systems and their consistenciesThe routes and insulation of the ducts and pipesCompactness of ducts,

through-holes and roomsThe purity of louvres, filters and valves Fine-tuning the system and automation controlUse and maintenanceSlide3

Ventilation and indoor airThe 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

.Slide4

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 kitchenDischarges from building materials and furniture.

Deficient ventilation causes:Stuffiness, smells Increased carbon dioxide - headache and exhaustionMoisture condensation – moisture damage Favourable habitat for microbesThe air must move freely between different rooms

Remember threshold gaps, keep doors open,…

VentilationSlide5

Good quality indoor airgood supply of fresh airthe recommended temperature of the room is 20-22o C; under 18

o C and over 23o C can cause health problemsair flow in the rooms, according to rules, is 0.2 m/s, recommended is 0.1 m/sgood indoor air has less than 900 ppm of co2 (co

2

is a good indicator of air quality)

t

he picture shows an indicator used to

measure air qualitySlide6

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/m

2

Living room e 0.5 l/s/m

2

.

The air is removed from the rooms with a lot of moisture or impurities.

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/m2walk-in closet, stores 3 l/s.

A

mount of ventilationSlide7

Natural ventilation

In natural ventilation, the warm air goes out through the flue and fresh air is brought in through valves on the walls. Slide8

Natural ventilationCommon 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.Slide9

Example of 150 m2 house with natural ventilation

Supply air downstairs:

3 ventilators

1 ventilation window ajar (1cm)

Exhaust air:

D

ownstairs

bathroom 1

exhaust air ventilator

Upstairs bedrooms

the

window is ajar and one exhaust air ventilator is over the window

Air quality:

Outdoor temperature -25

o

C

Two persons on both floors.

The carbon dioxide rate upstairs stays acceptable in the bedrooms Slide10

Mechanical extraction

Common in the 1960-1990’sAir is removed by fanAdjustment usually by the cooker hoodRequires sufficient fresh air and transfer air routesClosing the valves because of draught is a common problemThe action of the fans must be controlled

The valves must be cleaned regularly

Mechanical extraction

Outdoor air

Bedroom

Living room

Transferred air

Kitchen

Fan

Bathroom

Exhaust air

(Picture: Sisäilmayhdistys)Slide11

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 pre-heated 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.

Bedroom

Outdoor air

Fan

Living room

Kitchen

Mechanical input and extract ventilation

Air supply unit, heat recovery

Bath room

Outdoor air

Exhaust air

Supply air (heated)

Transferred air

Fire place switch

Cooker hood

(Picture: Sisäilmayhdistys)Slide12

Heat recoveryA 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

+22

+12

-5

+13

Fresh air

Exhaust air

Supply air

Extract air

Bridging air

Bridging sheet

Bridging sheet

(www.airwise.fi

)

(

www.eksergia.fi

)Slide13

HeatingThe 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

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Heat production methodsRenewable energy and hybrid systems are becoming more common

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Air source heat pumps ASHPIn 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. Slide16

Features of ASHPsThe 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 6.1

o

C)

In northern Sweden the SCOP values of the ASHPs were 1.7-2.6 (average temperature +1.3

o

C)Slide17

Comparing and choosing an ASHPASHPs 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.Slide18

Hybrid systemsA hybrid system means a common use of heat production methods. Heat air pumps are usually used with hybrid systems. 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.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. Slide19

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 sealingSlide20

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.

R

adiator heating is easy to adjust, but requires

relatively hot water.

The low temperature of floor heating feels nice but

means high heating power.

S

low 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%. Slide21

HVAC InstallationThe 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

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Installation routesWhen 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 installationsVentilation ducts, HEVAC-pipes, cable trays, insulations, luminairesPumps, dampers, sound traps,

Indicators, thermostats, sensors,… Slide23

Installation routes must be agreedCooperation 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.Slide24

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: Supply air ducts in warm spacesStack vents in warm spacesCold 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.

Installing and insulating roofsSlide25

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 mm-gap between the bonds. Slide26

The appropriate use of electricityChoose 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

L

aundering 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 lightingThe 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.Slide27

Fine-tuning and commissioning HVACThe 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

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Energy efficiency of building automation installationsIn 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.Slide29

Before commissioning the building, the HVAC systems must be tested and adjusted with the help of functional tests. adjustment of the air amountpre-adjustment of the radiator ventilatorsthe operation of thermostats and sensorsthe measurement of temperatures

the survey of the effects of heat loadtesting the cooperation of the systems the copies of functional diagrams and field books are left in the engine room and in the heat distribution roomensuring the operation of the control, alarm and report systemsthe users of the systems are guided to use the systems properlyThere must be enough time for functional tests.

The rooms must be able to close (the doors shut), so the measurements are reliable.

During the functional test can not be done any building works anymore.

Commissioning the HVAC

AC-engine

room in

Ideapark

Heat exchangerSlide30

Synchronizing the systemsThe 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:ventilation air supplyexternal heat loads e.g. solar radiationlights

the blast from the appliances

.

Thermostats should not be

covered by

fittings,

curtains, towels, etc. Slide31

RememberTight 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.T

he operating system must control: Quality, warmth and moisture of the airCarbon dioxide, volume of air and air flowEnergy consumptionMaintenance 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

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Authors: Olli Teriö, Juhani Heljo, Jaakko Sorri, Ulrika Uotila, Aki Peltola, Jari Hämäläinen, Heidi Sumkin. Translation Ulrika Uotila & Myra Bird.

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.