The document provides an overview of chilled beam systems, including their design, components, and applications for heating and cooling in large buildings. It explains different types of chilled beams, such as active and passive, and outlines their benefits and limitations, emphasizing energy savings and thermal comfort. Specific design and operational considerations are discussed, alongside practical applications in various settings.

1. Chilled Beam System
Design and Applications
Abhilash P, Mechanical Engineer, Bengaluru
October 29, 2024

2. OVERVIEW
October 29, 2024
1. Introduction
2. Components of Chilled
Beam
3. Types of Chilled Beam
4. Active Beam Overview
5. Active Beam Function
6. Why Chilled Beam
7. Air Side information
8. Water Side Information
9. Capacity Overview
10. Benefits and limitations
11. Applications with
Examples

3. Introduction
A Chilled Beam is a type of convection HAC system designed to heat or cool large
buildings
A Chilled beam is a air distribution device with integral coil installed within in order
provide Sensible Cooling and Heating
Primarily used in spaces where humidity can be controlled
Alternative to both Fan coil Units and VAV systems

4. Components of Chilled Beam
Air handling units
Major component within any chilled beam or chilled ceiling system
Role – to clean and condition the air as it enters the building
Mixing Boxes
Dampers are used in mixing boxes to regulate the mixture of fresh air and re-circulate air
Coils
Heat exchangers designed transfer the energy from a medium (usually water) to the air
Individual coil for heating and cooling

5. Types of Chilled Beams
Active chilled beams
These rely on primary air supply to provide the induction required.
Primary air takes care of the Latent and Sensible heat loads

6. Types of Chilled Beams
Passive Chilled Beams
No reliance on primary air supply. They work entirely on radiant
convection
These beams only take care of Sensible heat loads

7. Types of Chilled Beams
Multi Purpose Chilled Beams
These are active beams with additional components(smoke detectors,
lighting, sprinklers etc.)

8. Active Beam overview
A - Duct connection
S/A (primary air) from AHU
B – Primary air (P/A) plenum
static pressure forms and drives P/A
through nozzles
C – Perforated Grille
Room air (secondary air) is induced,
through grille, into coil
D – Unit mounted coil
2 or 4 pipe coil, cools/heats the
secondary coil
E – Mixed Air
P/A and secondary air mix
F – Discharge air
static pressure forms and drives P/A
through nozzles

9. How A.C.B Function

10. Hydronic Systems use water as energy transport medium
Water has many times thermal capacitance as compared to air
At a glance
Why Chilled
Beam ?

11. Air Side Information
Percentage relative to overall peak power for the conventional system

12. 0 5 10 15 20 35 40 45 50 55 60
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DRY BULB TEMPERATURE - °C
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PSYCHROMETRIC CHART
BAROMETRIC PRESSURE 760 mm of Mercury
-20 -15
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-5
Linric Company Psychrometric Chart, www.linric.com
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Outdoor Condition 30
deg, 40% RH
ADP
P/A temp. 12 deg
90% RH
Induced air temp.
away from coil
Sensible Cooling
by Secondary coil
Discharg
e air
Room condition 24
deg 50% RH
Room process
Δ w

13. Air Side Information(Psychrometrics)
Psychrometric review required to prevent condensation
Standard procedure :
Remove moisture from P/A at AHU
To prevent condensation on coil
**Space Dew point temp < EWT**
Q Latent = 2454*ρ*q* Δw(SI)
Q Sensible = 1.2*1.02*q*ΔT (SI)
Not all spaces are suitable for active beams:
Suitability engineering check – SHF >70% is ideal

14. Air Side Information(Primary Air)
Meet all ventilation requirements
- Min. vent.(O/A requirements)
- Remove 100% of the latent loads (Psychrometric)
- Provide enough Rm./A to meet Sensible loads
**Greatest of these sets the minimum air flow rate**
Decreased AHU & Duct Size
Decrease in fan energy ( majority of the energy is saved at the fan).

15. Water Side Information
Coil responsible for majority of the Sensible load
- Cooling and heating
Design requirements
- Water flowrate
- Temperatures(EWT, LWT)
- Generally EWT= 1 to 2 deg above SPACE dew point temperature

16. Capacity Overview
Air Side :
100% Latent energy capacity, increased by
- Increasing Δw between P/A & Rm/A
- Increasing Airflow rate
Minor Sensible capacity is increased by
- Increasing ΔT between P/A & Rm/A
- Increasing Airflow rate
Water Side :
Sensible capacity, is increased by :
- Increasing ΔT between water & Rm/A
- Increasing water flow rate
Total Capacity = Air Capacity + Water capacity

17. Chilled Beam Benefits
Significant Fan energy savings (lower overall S/A)
Increased air circulation with high thermal comfort
Smaller AHU & Ductwork
- Lower floor – floor heights
- Significant reduction in riser space
Low maintenance requirements
Water side free cooling may be an option
Quick response time
Low to Reasonable acoustics

18. Chilled Beam Limitations
Potential for higher first cost
Increase in pump energy (Small compared to Fan energy savings)
Limited air-side free cooling
High importance for building humidity control in Cooling
- Dehumidification at the AHU is required
- May require more sophisticated control for humidity control
- may not be acceptable for all spaces, based on latent loads

19. Applications
Sensible and Latent energy drive sustainability
Higher the Sensible – the greater the savings
Lower the Latent – the easier it is to control the dew point temperature of the space
(required due to no condensate pan)
Spaces with :
High Sensible loads & low Latent loads – Ideal
High Sensible loads & high Latent loads – may be suitable with careful examination
Low sensible loads & high Latent loads – not recommended

20. Applications
Open Office Area

21. Applications
Child Care Centre

22. Applications
Coffee shop

23. Examples – ACB in Laboratories
Find Qexhaust , QOZ using 6 ACPH.
Find Δw using QOZ and plot it on
Psychrometric chart.

24. Examples – ACB in Laboratories
Qexhaust = max[450 l/s,{(11 m)*(6 m)*(3.75 m)*(6 acph)*h/3.6}]
= max(450 l/s, 413 l/s)
= 450 l/s.
QOZ = (1-20%)*Qexhaust = 360 l/s = Qs
QL = 2500*ρ*Qs* Δw
ΔW = 0.55 g/kg
at 240
C, 50%RH humidity ratio is 9.5 g/kg
Ws = 9.5 – 0.55 = 8.95 g/kg (plotting it in psychrometric chart)

25. Examples – ACB in Laboratories

26. Examples – ACB in Computer Lab
Find QOZ using Building
regulations Part F or
ASHRAE 62.1.

27. Examples – ACB in Laboratories

28. Questions ?
wsp.com

29. Thank you!
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