chilled beam
DESCRIPTION
A chilled beam is a type of convection HVAC system designed to heat or cool large buildings. Pipes of water are passed through a "beam" (a heat exchanger) either integrated into standard suspended ceiling systems or suspended a short distance from the ceiling of a room. As the beam chills the air around it, the air becomes denser and falls to the floor. It is replaced by warmer air moving up from below, causing a constant flow of convection and cooling the room. Heating works in much the same fashion, similar to a steam radiator. There are two types of chilled beams. Some passive types rely solely on convection whilst there is a "Radiant"/convective passive type which cools through a combination of radiant exchange (40%) and convection (60%) which can provide higher thermal comfort levels, while the active type (also called an "induction diffuser") uses ducts to push ("induce") air toward the unit (increasing its heating and cooling capacity). The chilled beam is distinguishable from the chilled ceiling. The chilled ceiling uses water flowing through pipes like a chilled beam does; however, the pipes in a chilled ceiling lie behind metal ceiling plates, and the heated and cooled plates are the cause of convection and not the pipe unit itself. Chilled beams are about 85 percent more effective at convection than chilled ceilings.TRANSCRIPT
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CONTENTS
• INTRODUCTION• TYPES OF CHILLED BEAMS• CASE STUDY• ADVANTAGES AND DISADVANTAGES• CONCLUSIONS• REFERENCES
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INTRODUCTION
• HVAC system to heat or cool buildings• Pipes of water passed through a heat exchanger• Air around beam chills and denser air falls to the floor• Warmer air moves up • Water can carry more energy than air• A metal pipe of water 1 inch dia can carry same
energy as a 18 by 18 inch metal duct of air
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TYPES OF CHILLED BEAMS
• PASSIVE CHILLED BEAM
• ACTIVE CHILLED BEAM
• MULTI SERVICE CHILLED BEAM
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PASSIVE CHILLED BEAM• Simple device• Natural convection and radiation• Air flow based on temperature difference• Cooling output regulated by flow of chilled water• Not connected to ventilation system
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ACTIVE CHILLED BEAM• Grater cooling capacity• Primary air flow introduced• Control humidity and temperature hence high IAQ• Very quiet operation• High ventilation rate
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MULTI SERVICE CHILLED BEAM• Active or passive type• Integrate services like lighting, speaker systems ,sprinkler heads • Different services can be pre-fabricated off-site• Plug and play connections• Save time and hence cost of project
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CASE STUDY-ASTRA ZENECA,BOSTON
• In operation since 2000• Serve offices, laboratories, cafeteria ,atrium• No condensation issues• Cleaning was rarely required• 100% outside air system provides ventilation • They are planning for a new building using chilled beam
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ADVANTAGES AND DISADVANTAGES
• Simple to design and control• Constant volume supply air system• Almost no maintenance• Minimum cleaning• Reduction in energy use
• Not well known in our Industry• Higher construction cost• Affects traditional ceiling Appearance• Dew point concerns
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CONLUSIONS
• The initial cost is higher• Construction cost and type of building
decides type of chilled beam to be used• The operating and maintenance cost are
less• Provides high thermal comfort• Suitable for energy efficient and green
buildings • Not well known to our industry• Huge scope in India
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REFERENCES1. Can Chen, Wenjian cai, Youyi Wang, Chen Lin(2014),Energy and
Buildings: Performance comparison of heat exchangers with different circuitry arrangements for active chilled beam applications, vol.79,pages 164-172
2. Can Chen, Wenjian Cai, Karunakaran Giridharan, Youyi Wang(2014),Applied energy: A hybrid dynamic modeling of active chilled beam terminal unit, volume 128 , pages 133-143
3. ashrae.org4. Trane Engineers Newsletter volume 38–45. www.rehva.eu 6. www.reuters.com 7. www.semcoinc.com8. www.halton.com
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THANK YOU
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