Fundamentals of Hydronic Design

Transcription

1 Radiant Based HVAC Systems

2 Radiant Cooling & Heating

3 This educational material is copy written by Robert Bean, R.E.T., All Rights Reserved. If you wish to use this presentation for non commercial or for profit purposes, please contact for details and restrictions. Portions of this presentation are copy written by others including materials copy written 2005, by the American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc. ( Reprinted with permission from ASHRAE Applications Handbook. This material may not be copied nor distributed in either paper or digital form without permission. Some slides contained animations in the original.ppt format which have been eliminated in the conversions to Adobe s.pdf format.

4 Everything You Need to Know About Radiant You Learnt Before Kindergarten

5 Radiant Principles Thermography: Dr. Chapman (c/o Bob Hot Rod Rohr)

6 Radiant Principles Schlieren and shadowgraph: Dr. Gary Settles

7 Radiant Principles Software Modeling: Dr. decarli

8 Heat & Moisture Hot Air Convection Fire Radiation Wet Dry Water Evaporation Earth Conduction Cold

9 Thermal Comfort Dr. Fanger ANSI/ASHRAE Standard % Satisfaction

10 Thermal Comfort Five Factors To Consider Activity Clothing Operative Temperature Humidity Air Speed

11 Operative Temperature is a combination of the air and surface temperatures in the space.

12 Radiant conditioned spaces have higher operative temperatures.

13 Humans like consistent temperatures between their ankles and head < 5 F t

14 Humans like floor temperatures above 66 F when cooling and below 84 F when heating.

15 Transmitted Absorb Long Wave Energy Reradiated Reflect Emit

16 Humans prefer drafts below 3 fps in heating and humidity between 30% and 70% rh.

17 Radiant Principles Demonstration of: ASHRAE Thermal Comfort Program V.1.0, by C. Huizenga, M.Sc., Berkley University, Dr. Fountain, Environmental Analytics Thermal Comfort Calculator by Dr. Marsh, Welsh School of Architecture at Cardiff University Thermal Comfort Test Facilities, Circa 1970, Lingby, Denmark Danish Technical University

18 ASHRAE Comfort Program

19 ASHRAE Comfort Program

20 SQU1 Comfort Program

21 We Condition People not buildings!

22 Radiant System Performance What happens from start up to steady state? What happens to thermal comfort performance when the architecture changes? How much heat we can deliver from a floor?

23 Radiant Principles Thermal Lag at Start Up With Radiant Systems the air is only warm Air Temp because the surfaces are warm! Temperature of Room Mass

24 Radiant Principles Thermal Lag at Start Recovery Is Fast Think Light Radiant Transfer occurs as Air Temp soon as there is a difference in temperatures. Temperature of Room Mass

25 Think Thermal Battery

26 A Note on Slab Insulation Soil Moisture Content (by Thermal Conductivity, Btu/h.ft. o F mass) Sand Silt Clay Low, <4% Medium, 4 to 20% High, > 20% Table 3, Soil Thermal Conductivities, 2000 ASHRAE Systems and Equipment, pg 11.9 When it comes to specifying insulation types, the obligations of a professional designer are based on liability exposures. What is the standard of care expected from a design professional when specifying insulation? Are you below, at or above the benchmark in your decision? 2005, American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc. ( Reprinted with permission from ASHRAE Applications Handbook. This article may not be copied nor distributed in either paper or digital form without ASHRAE s permission.

27 As you go through the next slides imagine you are in the space and it is heated with air.

28

29

30

31

32

33

34 As you go through the next slides imagine you are in the space and it is heated with radiant.

35 2) As cooler surfaces are warmed they reradiate to other cooler surfaces. 1) Radiant energy travels from a heated surfaces to cooler surfaces

36 By raising the temperature of all the surfaces we can counteract the effects of adding windows.

37

38

39

40

41

42

43

44

45

46 How much heat can we deliver from a radiant surface?

47 Radiant Systems Performance Output Examples - Typical Total Heat Exchange Coefficient Mode Heating Cooling Surface Btu/h ft 2 F W/m 2 ºK Btu/h ft 2 F W/m 2 ºK Floor Wall Ceiling , American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc. ( Reprinted with permission from ASHRAE Applications Handbook. This article may not be copied nor distributed in either paper or digital form without ASHRAE s permission.

48 Example For Radiant Heated Floors (85 o F 72 o F) x 2.0 Btu /sf / o F = 26 btu/sf floor output

49 Total Heat Exchange Coefficient Radiant plus Convective Btu/h ft2 F

50 Typical High Mass Poured Floor System

51 Typical Low Mass Channel Floor System

52 The Role of Water and Air In Thermal Comfort Forced-Air Heating Radiant Heating Hybrid Heating dp IAQ Room Air RH Occupant, Room Mass HRV PMV Occupant, Room Mass MRT Room Air AUST OT Comfort Conditions Satisfied Customers

53 Would you like to see this presentation live? Contact or visit our website at. If you have questions contact us at our online forum at This material is presented as an educational service and is supported by downloading the Guide to Indoor Comfort Quality and the Architectural Guide to Radiant Based HVAC Systems Radiant Based HVAC Systems