Idronics 13: Hydronic Cooling
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"@KDEkCaleffi-NQSG North America, LDQHB@ (MB Inc. 6 ,HKV@TJDD1C9850 South 54th Street ,HKV@TJDD 6HRBNMRHMFranklin, WI 53132 3 % T: 414.421.1000 F: 414.421.2878 Dear Hydronic and Plumbing Professional, Dear Hydronic Professional, Cooling a living space using chilled water is not new. Visit a high-rise hotel nd roomWelcome in summer, to the and2 edition notice ofhow idronics it is cooled. – Caleffi’s Chances semi-annual are that design cool journal air enters for fromhydronic a vent professionals.located in the wall or ceiling. Behind the vent is a heat exchanger withThe chilled 1st edition water of flowing idronics into was it. released The water in January absorbs 2007 the and heat distributed from room to airover and80,000 carries people it back in North to a chillerAmerica. that It extractsfocused onthe the heat topic and hydraulic rejects separation.it outside From thethe building. feedback After received, being it’sre-cooled, evident wethe attained water returns our goal back of explaining to the room— the benefits completingand proper the application cooling cycle. of this modern design technique for hydronic systems. A Technical Journal WithIf you advances haven’t inyet technology, received a copyhydronic of idronics cooling #1, is you no canlonger do solimited by sending to high- in the from risesattached and other reader large response commercial card, or buildings. by registering Improvements online at www.caleffi.us in chilled-water. The publication will be mailed to you free of charge. You can also download the Caleffi Hydronic Solutions generators,complete journaldistribution as a PDFequipment file from and our pipingWeb site. have made hydronic cooling practical for residential and lighter commercial buildings. These systems offer advantagesThis second over edition traditional addresses forms air of and cooling, dirt in hydronicincluding systems. reduced Though electrical not a new CALEFFI NORTH AMERICA, INC energytopic usage,to our industry,simple zoning, the use thermalof modern storage high-efficiency and less equipmentinvasive installation. demands a 3883 W. Milwaukee Rd thorough understanding of the harmful effects of air and dirt, as well as knowledge Milwaukee, Wisconsin 53208 USA Thison issue how toof eliminate idronics them.explores Doing several so helps methods ensure of the hydronic systems cooling you design using will currentlyoperate available at peak efficiency products and and provide highlights long the trouble-free benefits service.and performance Tel: 414-238-2360 advantagesWe trust you of thesewill find systems. this issue We of hope idronics you a enjoyuseful it, educational and encourage tool and you a handyto FAX: 414-238-2366 sendreference us any for feedback your future about hydronic idronics system by e-mailing designs. usWe at also [email protected]. encourage you to send us feedback on this issue of idronics using the attached reader response card or by E-mail: idronics@caleffi .com Fore-mailing prior issues, us at [email protected] visit us at www.caleffi.us. and click on the Website: www.caleffi .us icon. There you can download the PDF files. You can also register to receive hard copies of future issues. To receive future idronics issues Sincerely, FREE, register online www.caleffi .us Mark Olson © Copyright 2013 Mark Olson General Manager, Caleffi North America, Inc. Caleffi North America, Inc. Printed: Milwaukee, Wisconsin USA General Manager & CEO INDEX 1. INTRODUCTION 2. A BRIEF HISTORY OF COOLING 3. BENEFITS OF CHILLED-WATER COOLING 4. CHILLED-WATER SOURCES 5. HEAT ABSORBERS FOR HYDRONIC COOLING 6. DESIGN CONSIDERATIONS 7. EXAMPLE SYSTEMS APPENDIX A: Piping symbol legend APPENDIX B: Sizing expansion tanks in chilled-water systems APPENDIX C: Psychometric chart Disclaimer: Caleffi makes no warranty that the information presented in idronics meets the mechanical, electrical or other code requirements applicable within a Mixed Sources Products from well-managed given jurisdiction. The diagrams presented in idronics are conceptual, and do not represent complete schematics for any specifi c installation. Local codes may forests, controlled sources and require differences in design, or safety devices relative to those shown in idronics. It is the responsibility of those adapting any information presented in idronics to recycled wood or fiber. verify that such adaptations meet or exceed local code requirements. Hydronic Cooling For Residential & Light-commercial Buildings (-31.#4"3(.- The ancient Egyptians learned to improve the comfort of their interior spaces during warm and dry weather Hydronic heating is a widely recognized technology, by hanging reeds in windows and trickling water down one that’s respected for delivering superior comfort them. The water evaporating from the surface of the and energy-efficient operation. However, one commonly reeds absorbed heat from the dry desert air as it passed perceived limitation of hydronics technology, especially in through. This was likely one of the earliest uses of residential and light-commercial buildings, is the ability to evaporative cooling. provide cooling. In ancient Rome, water supplied from aqueducts was Modern hydronics technology in combination with recent routed through the walls of buildings to provide cooling. developments in equipment that can efficiently produce Today, the use of water to cool surfaces that can then chilled water have made it practical to use hydronic- absorb heat is called radiant cooling based cooling in smaller buildings. Such systems offer several benefits relative to other methods of cooling. The Persians constructed “wind towers,” as seen in Figure 2-1. These structures created a column of rising This issue of idronics focuses on the hardware and design air similar to the draft created by a chimney. The rising air details appropriate to hydronic cooling in residential and would pull air through the attached building, creating air light-commercial buildings. It explores several methods currents that improved comfort. of hydronic cooling using a wide range of currently Figure 2-1 available hardware. It also shows how to integrate chilled-water cooling with several methods of modern hydronic heating to provide year-round comfort. !1($%'(23.18.%"..+(-& Most people living in developed countries take building cooling for granted. Most expect it in the office buildings or shops where they work. They also expect it in the cars, buses, airplanes and trains that carry them on their daily outings. With exception of some far northern homes or homes at high elevation, most homeowners now expect cooling in their homes. This expectation has become increasingly common over the last 50 Source: Wikipedia years. However, before that, building cooling was the In the mid-1700s, Benjamin Franklin demonstrated that exception rather than the rule. the rapid evaporation of volatile compounds such as alcohol and ether could cause the object from which the Attempts to limit the temperature of occupied spaces evaporation was occurring to drop as much as 7ºF below date back to early civilizations living in caves. Even in room temperature. Advances in chemistry during the tropical climates, the temperature of soil not exposed to 19th century laid the foundation for the first mechanical the sun, as well as shade from direct sunlight, provided cooling devices. These machines used ammonia as their some relief from what most of us would now consider refrigerant, alternately compressing and expanding it unbearably high temperatures and humidity levels. to transfer heat through a crude version of what is now known as the vapor compression cycle. 3 In colder climates, ice was often harvested from ponds windows located lower in the room. This arrangement and lakes during winter and stored as best as possible, created a weak “stack effect” within buildings that tended for cooling food during warmer weather. However, the to channel rising warm air within the building and use it amount of ice needed to cool a home of that vintage was to draw outside air in through exterior windows. Operable far more than what could be practically managed. transom windows can still be seen in many older homes Figure 2-2 and office buildings. Figure 2-3 shows an example of such a window, with its associated hardware that allows it to be operated from a normal standing height. When electricity became available, motorized fans helped provide relief to the discomfort associated with high air temperatures and high humidity. The increased air velocity across exposed skin encourages evaporation of perspiration, and thus allows better heat dissipation from the body. However, fans cannot reduce interior humidity, and thus were less effective during high humidity conditions. It is also important to know that an electric fan, operating in a closed room, adds heat to the room at a rate equal to the motor wattage. Figure 2-4 Until electricity became available in urban areas during the early 1900s, there was little relief from oppressive summer heat and humidity, especially on still days. Cross ventilation through open windows provided some relief, if there was a breeze to be had. Another technique that induced some air movement was the use of transom windows over interior doors, in combination with opened Figure 2-3a Figure 2-3b transom window The first use of refrigeration-based cooling for industrial warmer applications dates back to 1902, when Willis Carrier air developed an ammonia-based refrigeration system for a Brooklyn printing plant. Cooling for human comfort dates back to 1924, when a centrifugal chiller also designed by open window Willis Carrier was installed in a Detroit department store. The luxury it provided at the time soon lead to a market cooler air for cooling in movie theaters and other public buildings. By 1928, Carrier had created the first residential cooling devices. The continued development of air conditioning played a major role in the development of the southern United States during the 1900s. Source: http://blogs.usask.ca/1918_Eatons_Eager/2009/02/ 4 Figure 2-5 that a forced-air delivery system could deliver heating, cooling and ventilation, while a hydronic system could only provide heating.