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HEAT RECOVERY VENTILATION (HRV)

OVERVIEW

• Introduction

• Types of mechanical ventilation

• Heat recovery ventilation(HRV)

• Why HRV’s?

• Components of HRV

• Working

• Advantages of HRV

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OVERVIEW(Cont..)

• Disadvantages of HRV

• Operating a HRV

• HRV maintenance

• Similar to HRV’s

• ERV’s vs HRV’s

• Conclusion

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INTRODUCTION

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Ventilating is the process of replacing air in any space to provide high indoor air quality

Methods - mechanical/forced and natural types

Windows serve as a fine strategy for natural ventilation in mild climatic conditions. But natural ventilation depends on local conditions & wind shading, which are beyond human control

INTRODUCTION( Contd...)

Also, According to US Environmental Protection Agency, indoor air pollution levels are five times higher than outdoors which demands - Mechanical Ventilation

Mechanical ventilation systems circulate fresh air using ducts and fans, rather than relying on airflow through small holes or cracks in a home’s walls, roof, or windows

The advantages of mechanical ventilation are better air quality, more control and improved comfort

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TYPES OF MECHANICAL VENTILATION

Supply Ventilation Systems—Hot or Mixed Climates

Balanced Ventilation Systems—All Climates

Heat Recovery Ventilation

(HRV)

Energy Recovery Ventilation (ERV)

Exhaust Ventilation Systems—Cold Climates

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HEAT RECOVERY VENTILATION (HRV)

Heat recovery ventilation( HRV) is an energy recovery ventilation system using equipment known as a heat recovery ventilator which employs a counter-flow heat exchanger between the inbound and outbound air flow

HRV provides fresh air and improved climate control, while also saving energy by reducing heating (and cooling) requirements

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WHY HRV’s?

PreferHRV’s

To reduce energy

consumption

Improved air quality

Provide architectur

al fancy without

compromising

ventilation

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COMPONENTS OF HRV

Fans

Filters

Defrost mechanisms or Pre-heater

Operating controls

Ducts

Heat exchange core

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COMPONENTS OF HRV(Contd..)

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WORKING

Intake Air

Air from atmosphere is taken via ducts

Air is filtered

Heat Exchange Core

Moves through insulated ducts

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WORKING(Contd..)

Fresh Air To Building

Air reaches circulating fan

Fan distributes air throughout the building

Stale Air From Building

The air is collected

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WORKING(Contd.…)

Heat Exchange Core

Transfers the heating or cooling effect of stale air to the fresh air intake for next cycle

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WORKING(Contd..)

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ADVANTAGES OF HRV

Continuous supply of fresh air

Energy efficient ventilation

Condensation elimination

Comfort

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ADVANTAGES OF HRV(Contd..)

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• 1) Continuous Supply of Fresh Air– Filtered fresh air is circulated throughout day and

night

– Most people spend over 80% of their time indoors, 50% of all illnesses are either caused by, or aggravated by poor indoor air quality

– The HRV System continuously removes stale moist air creating a healthy environment

ADVANTAGES OF HRV(Contd..)

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• 2) Energy Efficient Ventilation– A HRV systems save money and reduce energy for

heating by re-using heat that is lost via standard extract systems

– A HRV is designed to operate continuously at low rate to minimize electrical energy consumption

ADVANTAGES OF HRV(Contd..)

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• 3) Condensation Elimination– Water vapour will be removed as it is produced

– As a result there is no moisture condensation which causes rot, damp, condensation or mould growth

– No fungal growth in bathrooms

ADVANTAGES OF HRV(Contd..)

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• 4) Comfort – Comfort levels are superior in a house fitted with a

Heat Recovery Ventilation system

– Irrespective of weather conditions, draught free balanced ventilation is provided all the time

– Extra security when windows are closed

DISADVANTAGES OF HRV

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Needs regular maintenance

Filters need cleaning or replacing every 6–12 months.

High installation cost

Not much beneficial in hot weather conditions

OPERATING A HRV

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• Controls– Allows user to adjust the rate of ventilation and

humidity level to certain extend– Depending upon models & installation, controls

may be located on HRV itself or in rooms– Pollutant sensors are also installed– Can turned off HRV, when required

HRV MAINTENANCE

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Clean or replace air filters

Clean the heat-exchange core

Inspect ductwork

Arrange for annual servicing

Clean the condensate drain and pan

SIMILAR TO HRV’s

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An alternative system called energy recovery ventilation (ERV) works in a similar way as heat recovery ventilators

Transfers moisture from the outgoing airstream to the incoming air

It’s the disadvantage of ERV, which are covered up by the HRV’s

HRV’s vs. ERV’s

HRV core

ERV core

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CONCLUSION

Provides fresh air and improved climate control

Most efficient in saving energy

All buildings require source of fresh air, the need for HRVs has become obvious

The best technology currently available for reducing radon levels

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REFERENCES

• Solutions for Energy Efficient and Sustainable Heating of Ventilation Air: A Review A. Žandeckis*, K. Kļaviņa, M. Dzikēvičs, V. Kirsanovs and G. Žogla,Journal of Engineering Science and Technology Review 8 (3) (2015) 98-111

• Akbari K., Oman R.(2013).”Impacts of Heat Recovery Ventilators on Energy Savings and Indoor Radon in a Swedish Detached House.”WSEAS Transactions on Environment & Development, 9(1),2224-3496.

• Natural Resources Canada’s Office of Energy Efficiency(2012), “Heat recovery ventilators”,HTTP://WWW.HOUSING.YK.CA/PDF/HRV.PDF

• Akbari et.al (2013) "Impacts of heat recovery ventilators on energy savings and indoor radon level", Management of Environmental Quality: An International Journal, Issue 5,Volume 24, Page 682 – 694

• Juha Jokisalo , Jarek Kurnitski , Mika Vuolle , Antti Torkki(2003) ”Performance of Balanced Ventilation with Heat Recovery in Residential Buildings in a Cold Climate”The International Journal of Ventilation,2(4) 223 -236

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• Ambrose Dodoo, Lief Gustavasson, Roger Sathre (2011) “Primary energy implications of ventilation heat recovery in residential buildings” Energy and Buildings, 43(7) 1566 – 1572

• Efficiency “International journal of ventilation 6 Olli Seppanen (2008)” Ventilation Srtategies for Good Indoor Air Quality and Energy(4)297-306

• P.Wargocki(2013) “The Effects of ventilation in homes on health” International journal of ventilation 12(2)101-118

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