Radiant cooling systems circulate cool water through ceiling, wall, or floor panels to absorb heat from occupants and interior spaces. They are more efficient and comfortable than traditional air circulation systems. Radiant cooling systems have comparable initial costs but provide lifetime energy savings of 5-30% over air systems due to water's higher heat transfer capacity. This document describes the components, design, and benefits of a radiant cooling system installed in an office building in Delhi, India. Experimental results found the radiant system saved 17-26% more energy than a traditional variable air volume system.

1. Submitted To:
Er. Gurmeet Singh
Er. Pankaj Sharma Sir
Er. Deepak Bhijwani
Department of
Mechanical Engineering
Submitted By:
Parvez Sheikh
Vaibhav Mathur
Qushar Alam
Mukesh Mitharwal
Rahul Vashist
Manish Kumar
Manjeet Kumar Giri
Presentation on Radiant Cooling
1

2. 2Introduction
Unlike most cooling systems in California which circulate cold air to
maintain comfort most radiant cooling system circulate cool water through ceiling
wall, or floor panels from that water is then absorbed by the occupants and interior
spaces.
According to dynamics of thermal radiation these radiant cooling systems which are
popular in Europe are rarely found in Delhi university buildings however. Radiant
cooling systems are more efficient more comfortable more attractive and more
healthful then systems that circulate air. A lack of familiarity with radiant cooling
technology and lingering memories of moisture control problem experience by a few
pioneering system installed decades ago.
There are several good reasons designer should consider including radiant cooling
system. The first cost for the radiant system are comparable with those for the
traditional air volume system but their lifetime energy savings over air volume
system are routinely % or even more .The produce impressive savings. Since water
has roughly 3500 times the energy transport capacity of air. System can transport a
given amount of cooling with less than 5% of energy required to deliver cool air with
fans.

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Components of Radiant Cooling
1.Chiller
2.Header Pipe(Copper &Aluminum)
3.Folk Ceiling
4.Pipe(WIRRSBO hepx “5/8 in SDR9 PEX-a 100 PSI 180F/ 80 PSI
5.Temperature Regulator
6.Pressure Gauge
7.Valves
8.Supply fan & Return fan
9.Flow meter
10.Diffuser

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Basic Design data for conditioned Space
Table (3.1) describes basic design data for the conditioned space. Figure 4 and 5
indicate layout and direction of the office building respectively. Table 1: Basic
design data for the conditioned space
System description- Ceiling radiant cooling panel
Room size- 4.22m x 2m x 3.05m (height)
Occupancy level- 2 persons
Lighting- 2 fluorescent tube Lamps, (1)1200mm,T12
Other assumption- All walls and ceiling are exposed to the sun,
no moisture generation source except
occupants, ventilation, and infiltration.
Ambient temperature under floor air is 29°C

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Basic concept of Radiant Panel Cooling Systems
Radiant cooling ceiling panels contain chilled water running through the pipes
that are bonded to the non-visible side of the panels. The ceiling panels
function as heat exchangers between the room air and the chilled water. The
ceiling absorbs heat from the heat sources in a room and exchanges it with
circulating chilled water. The chilled water is then pumped to a chiller, re-
cooled and returned to the ceiling
Types of Hydronic Radiant cooling systems
There are various types of hydronic radiant cooling systems: metal ceiling
panels, chilled beams, tube imbedded in ceilings, walls, and floors [5]. Figures
1, 2 and 3 show the various types of hydronic radiant cooling systems.

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7. 7Cooling load calculation
The cooling load of the conditioned space (3.5kW) was
calculated by using computer program (Matlab) for
transient heat flow through the walls and ceiling. Other
heat loads were determined by the standard ASHRAE
method. Then, the radiant cooling panel system was
designed.
Specification of ceiling Radiant cooling Panel
Four (1.3m x 1.05m) ceiling radiant cooling panels
(aluminum sheet) are installed under the ceiling of the
conditioned space. Each panel consists of thirteenth
serpentine copper tubes fixed down side (Figure 6),
and insulated with fiberglass at the top of the other side
to prevent heat gains from the plenum space (between
the roof and panel) as shown in Figure 7. Other
descriptions of the panels are available in Table 2 and
Figure 8.

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9. 9
Model Space Condition
The block diagram of the structured radiant ceiling panel with
dedicated outdoor air system (DOAS) is shown in Figure 9. The chilled
water passes to the fan coil unit to reduce the ambient temperature so
as to supply an air temperature of 12oC and then, enters the panel
with 14.2oC and exits with 16.8oC. The chilled water is then pumped
to a chiller, recooled and returned to the ceiling. The function of fan coil
unit is to remove the latent and partial sensible heat load of the space.

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12. 12
Types of Heat Transfer

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15. 15
The Benefits of PEX-a
Currently, three methods for producing crosslinked polyethylene (PEX)
tubing exist:
• Engel or peroxide method (PEX-a)
• Silane method (PEX-b)
• Electron beam (E-beam) or radiation method (PEX-c) All three processes
generate tubing that is crosslinked to varying degrees and is acceptable
for potable water distribution applications according to ASTM F876 and
F877 standards.

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Engel Method (PEX-a) — Uponor manufactures Engel-method, PEX-a tubing. The
PEX tubing industry considers this tubing superior because the crosslinking is done
during the manufacturing process when polyethylene is in its amorphic state (above the
crystalline melting point). The Engel method produces the highest degree of
crosslinking — approximately 85% —resulting in a more uniform product with no weak
links in the molecular chain. PEX-a has a high degree thermal memory — meaning
kinked tubing can be reshaped with the use of a heat gun.
Silane Method (PEX-b) — PEX-b tubing is crosslinked after the extrusion process by
placing the tubing in a hot water bath or steam sauna. The degree of crosslinking for
PEX-b is typically around 65 to 70%. This method produces PEX that is not as evenly
crosslinked and with a lower degree of thermal memory than PEX-a.
E-beam Method (PEX-c) — PEX-c uses an electron beam to achieve crosslinking after
the extrusion process. The PEX-c method requires multiple passes under the beam to
reach a 70 to 75% degree of crosslinking. Side effects of this process are discoloration
due to oxidation (from natural white to yellow, unless other pigment is added) and a
slightly stiffer product.

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PEX-a Distinctions The properties of PEX-a tubing make it the most flexible PEX on the
market. Flexibility gives PEX-a tubing the tightest end radius available — as little as
31⁄2" for 1⁄2" tubing. Its flexibility also greatly reduces kinks. However, if there is the
rare occurrence of kinked tubing, the thermal memory of PEX-a means the tubing can
be repaired with a simple shot of heat from a heat gun.
The shape memory of PEX-a tubing offers the unique opportunity for fitting
connections. Shape memory allows PEX-a tubing to expand and then shrink back to
normal size, creating strong, durable and reliable fitting connections.
Finally, of the three types of PEX, PEX-a tubing offers the greatest resistance to crack
propagation (how a crack grows). This resistance means if a crack occurs in PEX-a
tubing, it is least likely to grow over time and cause leaks or damage.
Uponor Tubing With more than 40 years of service — longer than any other PEX
manufacturer in North America — Uponor is the leader in PEX tubing for radiant
heating, plumbing and fire safety systems. More than 2 billion feet of Uponor PEX
tubing is in service in North America alone, and more than 15 billion feet of tubing is
installed worldwide. With that kind of history, you can count on Uponor PEX to offer the
highest quality tubing for all your application needs.

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TruFLOW Manifold Exploded View:

19. 19Supply Temperature:
Ts = Tavg + t/2
Return Temperature:
Tr = Tavg - t/2

20. 20Results
The following, depict the results obtained after testing the system. From Table
3 it is found that the experimental results (DBT and RH of outside air) show
relative variance when compared with design conditions. The variation is
attributed to the fact that experiments were conducted during autumn season
instead of summer season for which design conditions were set. On the other
hand, the RH and DBT of inside air of experimental results show an increase
of 4.42% and 3.4% in each respectively.

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Figure 10, shows a comparison between CRCP/DOAS and VAV system for
peak power demand through this study. It is clear that from this figure that the
CRCP/DOAS system with recirculation air was found to save 17.3% energy
over the VAV system with return air. On the other hand, the CRCP/DOAS
system with 100% fresh air can save more than 26.1% of input power over a
VAV system with 100% fresh air.
The reason for this is that the CRCP/DOAS uses minimum supply air (86.8l/s)
than VAV system (157.83 l/s) in case if recirculation air is used in each
respectively. Also, the CRCP/DOAS uses supply air of (140l/s) than VAV system
which uses (202.62 l/s) in case if 100% fresh air is used in each respectively.
The other reason is attributed to the energy used by its pump (19.2W) which is
less than by fan (40W) in VAV system.

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23. 23
Costing
Chiller = 7000/-
Supply & Return Fan = 4000/-
Header Pipe = 4000/-
Folk Ceiling = 8000-9000/-
Radiant PEX+ Pipe = 6000-8000/-
4 Valves = 2000/-
Temperature Sensors = 1500/-
2 Pressure Gauge = 2000/-
Total Costing = 39000-40000/-

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YOU