Radiant cooling

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.

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

2. 2 Introduction 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.

3. 3 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

4. 4 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

5. 5 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. 7 Cooling 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.

16. 16 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.

17. 17 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.

18. 18 TruFLOW Manifold Exploded View:

19. 19 Supply Temperature: T s = T avg + t/2 Return Temperature: T r = T avg - t/2

20. 20 Results 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.

21. 21 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/-

24. 24 THANK YOU