1. Norwegian Building Research Institute P.O.Box 123 Blindern Forskningsveien 3B 0314 Oslo Norway  +47 22965500  +47 22965725 Contact persons: J.T. Brunsell (jorn.brunsell.@byggforsk.no)jorn.brunsell.@byggforsk.no P. Blom (peter.blom@byggforsk.no)peter.blom@byggforsk.no E. Skaaret (eimund.skaaret@byggforsk.no)eimund.skaaret@byggforsk.no T. Hestad (trygve.hestad@byggforsk.no)trygve.hestad@byggforsk.no NatVent project,WP3/A3.3 Natural ventilation with heat recovery NatVent project,WP3/A3.3 Natural ventilation with heat recovery Heat recovery Heat recovery Back to “WP3” Back to “WP3” Why & target Why & target 2 Systems 2 Systems NBI’s system NBI’s system Measuring Conclusions More... More... Driving forces Driving forces NatVent

2. Heat recovery Heat recovery Back to “WP3” Back to “WP3” Why & target Why & target 2 Systems 2 Systems NBI’s system NBI’s system Measuring Conclusions More... More... Driving forces Driving forces Energy recovering from natural ventilation systems Because of two reasons in moderate and cold climate: 1.To recover energy 2.To supply preheated air Work content WP 3.3 Natural ventilation with heat recovery Requirements of a system with heat recovery for an office building. Evaluate the energy saving potential. Develop advanced systems with heat recovery Laboratory testing of system. Work content WP 3.3 Natural ventilation with heat recovery Requirements of a system with heat recovery for an office building. Evaluate the energy saving potential. Develop advanced systems with heat recovery Laboratory testing of system.

3. NatVent Heat recovery Heat recovery Back to “WP3” Back to “WP3” Why & target Why & target 2 Systems 2 Systems NBI’s system NBI’s system Measuring Conclusions More... More... Driving forces Driving forces Distribution of natural driving forces

4. NatVent Heat recovery Heat recovery Back to “WP3” Back to “WP3” Why & target Why & target 2 Systems 2 Systems NBI’s system NBI’s system Measuring Conclusions More... More... Driving forces Driving forces Internal air supply - system 1 (1...)

5. NatVent Heat recovery Heat recovery Back to “WP3” Back to “WP3” Why & target Why & target 2 Systems 2 Systems NBI’s system NBI’s system Measuring Conclusions More... More... Driving forces Driving forces Internal air supply - system 2 (2|)

6. NatVent Heat recovery Heat recovery Back to “WP3” Back to “WP3” Why & target Why & target 2 Systems 2 Systems NBI’s system NBI’s system Measuring Conclusions More... More... Driving forces Driving forces NBI’s NatVent system with heat recovery (1...)

7. NatVent Heat recovery Heat recovery Back to “WP3” Back to “WP3” Why & target Why & target 2 Systems 2 Systems NBI’s system NBI’s system Measuring Conclusions More... More... Driving forces Driving forces System outdoors (2...)

8. NatVent Heat recovery Heat recovery Back to “WP3” Back to “WP3” Why & target Why & target 2 Systems 2 Systems NBI’s system NBI’s system Measuring Conclusions More... More... Driving forces Driving forces System Indoors (3|)

9. NatVent Heat recovery Heat recovery Back to “WP3” Back to “WP3” Why & target Why & target 2 Systems 2 Systems NBI’s system NBI’s system Measuring Conclusions More... More... Driving forces Driving forces Measurements Temperatures Outdoor Indoor Outgoing air Incoming air Pressure drops Across the filter Across both sides of the heat recovery Total for the system including ducts and terminals Velocity In the ducts, gives the air flow Wind Driving forces Natural –Temp. dif. –Wind Assisting fan Filter efficiency Heat recovery efficiency

10. NatVent Heat recovery Heat recovery Back to “WP3” Back to “WP3” Why & target Why & target 2 Systems 2 Systems NBI’s system NBI’s system Measuring Conclusions More... More... Driving forces Driving forces Pressure losses at design value: 400 l/s Extract side Supply side

11. NatVent Heat recovery Heat recovery Back to “WP3” Back to “WP3” Why & target Why & target 2 Systems 2 Systems NBI’s system NBI’s system Measuring Conclusions More... More... Driving forces Driving forces Measurement modes Without any fans With extract fan (most of the time) With both extract and supply fan

12. NatVent Heat recovery Heat recovery Back to “WP3” Back to “WP3” Why & target Why & target 2 Systems 2 Systems NBI’s system NBI’s system Measuring Conclusions More... More... Driving forces Driving forces Temperatures & air flow (without fans)

13. NatVent Heat recovery Heat recovery Back to “WP3” Back to “WP3” Why & target Why & target 2 Systems 2 Systems NBI’s system NBI’s system Measuring Conclusions More... More... Driving forces Driving forces Air Flow vs Natural Driving forces

14. NatVent Heat recovery Heat recovery Back to “WP3” Back to “WP3” Why & target Why & target 2 Systems 2 Systems NBI’s system NBI’s system Measuring Conclusions More... More... Driving forces Driving forces Temperatures & air flow (extract fan running)

15. NatVent Heat recovery Heat recovery Back to “WP3” Back to “WP3” Why & target Why & target 2 Systems 2 Systems NBI’s system NBI’s system Measuring Conclusions More... More... Driving forces Driving forces Extract & supply fan (without pump running)

16. NatVent Heat recovery Heat recovery Back to “WP3” Back to “WP3” Why & target Why & target 2 Systems 2 Systems NBI’s system NBI’s system Measuring Conclusions More... More... Driving forces Driving forces Fan power & natural driving forces (pump turned off)

17. NatVent Heat recovery Heat recovery Back to “WP3” Back to “WP3” Why & target Why & target 2 Systems 2 Systems NBI’s system NBI’s system Measuring Conclusions More... More... Driving forces Driving forces Extract fan power vs nat. driving force (regulating at 400 l/s)

18. NatVent Heat recovery Heat recovery Back to “WP3” Back to “WP3” Why & target Why & target 2 Systems 2 Systems NBI’s system NBI’s system Measuring Conclusions More... More... Driving forces Driving forces Conclusions Heat recovery should be considered in natural ventilated office buildings in cold climates Practical concepts existed and have been further developed Concepts must involve a close integration with the building design Heat recovery may require assisting fans for stabilising air flows. Assisting energy efficient fans may act as efficient flow controllers Measured heat recovery efficiency is 0,5 but can be further improved Natural ventilation with heat recovery is economic and technical competitive with traditional systems today

19. More information... You can fin more information on: Heat recovery and the work carried out in the framework of Task 3.3. in the document ‘3.3_heat recovery.pdf’ in the directory \Reports\ Technological solutions You can fin more information on: Heat recovery and the work carried out in the framework of Task 3.3. in the document ‘3.3_heat recovery.pdf’ in the directory \Reports\ Technological solutions You can read and print pdf-files with the Acrobat® Reader ®3.0. Program. This program is free. Download it from the Acrobat web site: www.adobe.com OR run the installation file ar32e301(1).exe in the directory \Installation You can read and print pdf-files with the Acrobat® Reader ®3.0. Program. This program is free. Download it from the Acrobat web site: www.adobe.com OR run the installation file ar32e301(1).exe in the directory \Installation Heat recovery Heat recovery Back to “WP3” Back to “WP3” Why & target Why & target 2 Systems 2 Systems NBI’s system NBI’s system Measuring Conclusions More... More... Driving forces Driving forces NatVent