ASHRAE Journal - January 2013 - 36

is circulated to each loop of tubing through a manifold that serves multiple floor loops (Photo 1, Page 34). For capacity control, the system may be configured as a constant flow variable temperature system or a variable flow (multizone pulsed constant flow) with constant fluid inlet temperature setpoints for heating and cooling modes. The author almost always uses the variable flow system because it allows inexpensive individual zone control with only the addition of two-way control valves. A constant flow system with variable inlet temperature requires a pump and a mixing valve or a variable temperature fluid source for each temperature control zone. Zones in these systems tend to be much larger and cannot so easily track solar patterns across the floor of a large sunspace. The distribution manifold for a constant temperature variable flow system will generally contain, for each loop, a manual air vent, and either a manual balancing valve, or an automatic control valve to modulate fluid flow through each loop. When individual floor loop control is not required, the manifold itself will have a control valve to modulate flow through all loops on that manifold. The author’s standard design varies flow either at the loop or the manifold, based upon maintenance of a setpoint at a temperature sensor embedded

in a representative location in the slab. A digital controller determines the setpoint at any time and determines whether the system is in heating or cooling mode. Algorithms for setpoint determination and heating/cooling changeover will be discussed later. Supply water in each mode of operation (heating or cooling) is typically fixed at 60°F (15.6°C) for cooling in humid climates and at 100°F (37.8°C) for heating. Because the slab system provides no ventilation or dehumidification, it is almost always accompanied by a dedicated outdoor air system (DOAS). These systems often have been described in the literature.5 For applications in humid climates, the DOAS should be controlled to maintain a supply air dew-point temperature no greater than 54°F (12.2°C), during all hours of operation. This dew-point temperature setpoint may be lower for certain high density occupancy types. In humid climates, the DOAS may require a low flow recirculation dehumidification mode for control of the maximum interior dew-point temperature during unoccupied periods. The DOAS and the floor system will require heating and cooling sources for the conditioning water. The temperature requirements for the floor system are typically much less extreme than those for the DOAS, particularly in humid or continental climates. Improved energy efficiency can accrue from supply-

(Supersedes ANSI/ASHRAE Standard 34-2007) Includes ANSI/ASHRAE Addenda listed in Appendix H

ANSI/ASHRAE Standard 34-2010

Visit AsHRAE BookstoRE At AHR Expo

ASHRAE STANDARD Designation and Safety Classification of Refrigerants

For Refrigerant Safety, 1+1>2
Inclu

See Appendix H for approval dates by the ASHRAE Standards Committee, the ASHRAE Board of Directors, and the American National Standards Institute.

This standard is under continuous maintenance by a Standing Standard Project Committee (SSPC) for which the Standards Committee has established a documented program for regular publication of addenda or revisions, including procedures for timely, documented, consensus action on requests for change to any part of the standard. The change submittal form, instructions, and deadlines may be obtained in electronic form from the ASHRAE Web site (www.ashrae.org) or in paper form from the Manager of Standards. The latest edition of an ASHRAE Standard may be purchased from the ASHRAE Web site (www.ashrae.org) or from ASHRAE Customer Service, 1791 Tullie Circle, NE, Atlanta, GA 30329-2305. E-mail: orders@ashrae.org. Fax: 404321-5478. Telephone: 404-636-8400 (worldwide), or toll free 1-800-527-4723 (for orders in US and Canada). For reprint permission, go to www.ashrae.org/permissions. © Copyright 2010 American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc.

ASH RAE STAN Safet DAR y Sta D nd R
efrige
ISSN 1041-2336

NSI/A (Sup SHRA des AN ersedes E Stan SI/ASH ANSI/A dard SH RAE 15-201 Adde RAE Stan nda lis da 0 ted in rd 15-200 7) Appe ndix G

A

ratio

ard f or n Sys tems

ANSI/ASHRAE Standards 15-2010 and 34-2010 Set Now Available Together, they add up to safer refrigeration systems. Standard 34 describes a shorthand way of naming refrigerants and assigns safety classifications based on toxicity and flammability data, while Standard 15 establishes procedures for operating equipment and systems when using those refrigerants. ASHRAE offers the standards as a set.

American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc. See
Appe 1791 Tullie dCircle NE, Atlanta, GA 30329 an the ndix G for apwww.ashrae.org Ameri proval can da Nation al Sta tes by the AS This sta ndard s Institu HRAE Sta the Sta ndard is un ndard te. de ndard s Comm s Comm r continuou sions, ittee, the s inc the sta luding pro ittee has est maintenance ASHR ced nd AE Bo ab the AS ard. The cha ures for tim lished a do by a Stand ard of ing Sta Direct HRAE cumen ors, ndard an AS Web site nge submit ely, documen ted Pro HRAE ted, con program (www.a tal form, Custo Stand for reg ject Comm instructio sensus shrae me ard ma ittee (SS ular pu ns, act 321-5 r Service, y be pu .org) or in PC) for 478. Tel paper and deadline ion on reque blication of 1791 rchase which Tu for ad For rep ep sts for s may rint pe hone: 404-6 llie Circle, NEd from the m from the chang denda or rev be ob ASHR Ma rmission tain e to an i36 , y , go to -8400 (wo Atlanta, GA AE Web nager of Sta ed in electr © Copyr rldwid onic for part of ndard www.a site (ww 30329-2 ight 20 shrae.or e), or toll m fro 305. E-m w.ashrae s. The late 10 Am fre g/perm st editio m .org) ail: erican ission e 1-800-52 Society s. 7-472 orders@ashr or from AS n of 3 (for of Heatin HRAE orders ae.org. Fa g, Refrig x: in US erating and Ca 404and Air nada). -Cond itionin g Engin eers, Inc . ISSN 1041-23 36

Ame

rican So and A ciety of H ea ir-Co nditio ting, Refr igera ning 1791 Tullie tin Circle Engine ers, In g NE, At lant c. w a, GA
ww.as 3032 hrae.o 9 rg

Price: $89 (ASHRAE Member $75) Product code: 86019

To order, call 1-800-527-4723 (US/Canada) or 404-636-8400 (worldwide) or visit www.ashrae.org/standard15and34-2010
www.info.hotims.com/44628-202
Standard 15 & 34 half page.indd 1 1/24/2011 9:53:21 AM

36

ASHRAE Journal

January 2013



ASHRAE Journal - January 2013

Table of Contents for the Digital Edition of ASHRAE Journal - January 2013

ASHRAE Journal - January 2013
Contents
Commentary
Industry News
Letters
Meetings and Shows
Feature Articles
Long-Term Commercial GSHP Performance: Part 6: Maintenance and Controls
Thermally Active Floors, Part 1
Technology Award Case Studies:
Aquathermal Systems
Standing Columns
Data Centers
People
Emerging Technologies
IAQ Applications
Engineer's Notebook
Washington Report
Refrigeration Applications
Classified Advertising
Advertisers Index
ASHRAE Journal - January 2013 - ASHRAE Journal - January 2013
ASHRAE Journal - January 2013 - Cover2
ASHRAE Journal - January 2013 - 1
ASHRAE Journal - January 2013 - 2
ASHRAE Journal - January 2013 - Contents
ASHRAE Journal - January 2013 - Commentary
ASHRAE Journal - January 2013 - 5
ASHRAE Journal - January 2013 - Industry News
ASHRAE Journal - January 2013 - 7
ASHRAE Journal - January 2013 - 8
ASHRAE Journal - January 2013 - 9
ASHRAE Journal - January 2013 - 10
ASHRAE Journal - January 2013 - 11
ASHRAE Journal - January 2013 - 12
ASHRAE Journal - January 2013 - 13
ASHRAE Journal - January 2013 - 14
ASHRAE Journal - January 2013 - 15
ASHRAE Journal - January 2013 - Letters
ASHRAE Journal - January 2013 - 17
ASHRAE Journal - January 2013 - Meetings and Shows
ASHRAE Journal - January 2013 - 19
ASHRAE Journal - January 2013 - 20
ASHRAE Journal - January 2013 - 21
ASHRAE Journal - January 2013 - 22
ASHRAE Journal - January 2013 - 23
ASHRAE Journal - January 2013 - Long-Term Commercial GSHP Performance: Part 6: Maintenance and Controls
ASHRAE Journal - January 2013 - 25
ASHRAE Journal - January 2013 - 26
ASHRAE Journal - January 2013 - 27
ASHRAE Journal - January 2013 - 28
ASHRAE Journal - January 2013 - 29
ASHRAE Journal - January 2013 - 30
ASHRAE Journal - January 2013 - 31
ASHRAE Journal - January 2013 - Thermally Active Floors, Part 1
ASHRAE Journal - January 2013 - 33
ASHRAE Journal - January 2013 - 34
ASHRAE Journal - January 2013 - 35
ASHRAE Journal - January 2013 - 36
ASHRAE Journal - January 2013 - 37
ASHRAE Journal - January 2013 - 38
ASHRAE Journal - January 2013 - 39
ASHRAE Journal - January 2013 - 40
ASHRAE Journal - January 2013 - 41
ASHRAE Journal - January 2013 - 42
ASHRAE Journal - January 2013 - 43
ASHRAE Journal - January 2013 - 44
ASHRAE Journal - January 2013 - 45
ASHRAE Journal - January 2013 - 46
ASHRAE Journal - January 2013 - 47
ASHRAE Journal - January 2013 - Aquathermal Systems
ASHRAE Journal - January 2013 - 49
ASHRAE Journal - January 2013 - 50
ASHRAE Journal - January 2013 - 51
ASHRAE Journal - January 2013 - 52
ASHRAE Journal - January 2013 - 53
ASHRAE Journal - January 2013 - 54
ASHRAE Journal - January 2013 - 55
ASHRAE Journal - January 2013 - 56
ASHRAE Journal - January 2013 - 57
ASHRAE Journal - January 2013 - 58
ASHRAE Journal - January 2013 - 59
ASHRAE Journal - January 2013 - 60
ASHRAE Journal - January 2013 - Data Centers
ASHRAE Journal - January 2013 - 62
ASHRAE Journal - January 2013 - 63
ASHRAE Journal - January 2013 - People
ASHRAE Journal - January 2013 - Emerging Technologies
ASHRAE Journal - January 2013 - 66
ASHRAE Journal - January 2013 - 67
ASHRAE Journal - January 2013 - IAQ Applications
ASHRAE Journal - January 2013 - 69
ASHRAE Journal - January 2013 - 70
ASHRAE Journal - January 2013 - 71
ASHRAE Journal - January 2013 - Engineer's Notebook
ASHRAE Journal - January 2013 - 73
ASHRAE Journal - January 2013 - 74
ASHRAE Journal - January 2013 - 75
ASHRAE Journal - January 2013 - Washington Report
ASHRAE Journal - January 2013 - Refrigeration Applications
ASHRAE Journal - January 2013 - Classified Advertising
ASHRAE Journal - January 2013 - Advertisers Index
ASHRAE Journal - January 2013 - 80
ASHRAE Journal - January 2013 - Cover3
ASHRAE Journal - January 2013 - Cover4
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