Reminder: Solar and Terrestrial Radiation

Transcription

1 ACTIVE SOLAR THERMAL SYSTEMS Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 1 Reminder: Solar and Terrestrial Radiation wavelengths shorter longer the energy action is here not to scale Heating, Cooling, Lighting: Norbert Lechner Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 2 1

2 Reminder: Solar Radiation Components some energy lots of energy Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 3 Reminder: Solar Paths focus of sunpath diagrams is direct solar NORTHERN HEMISPHERE orientation and tilt of a surface will affect magnitude of received solar energy Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 4 2

3 Possible Solar Energy Conversions Helio-chemical conversion Solar radiation to chemical energy Photosynthesis: food, biomass Helio-electrical conversion Solar radiation to electrical energy Photovoltaics (PV) Helio-thermal conversion Solar radiation to heat energy Passive and active approaches Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 5 Active Solar Thermal Systems Configuration Options Water or air as the heat exchange medium Flat-plate or concentrating collector configurations Fixed or tracking collector installations Potential Applications Domestic hot water (potable water) Space heating Space cooling (via an absorption chiller) Process heat (product production) Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 6 3

4 Solar Thermal System Components These systems involve an energy source (solar radiation a renewable resource with zero carbon emissions) harvested by a collector with aperture (the aperture defines system size ) and absorber (to convert radiation to heat) that is connected to heat storage (generally required by the nature of the cyclical solar source) and often involving a backup heat source (for extreme conditions). The collected heat is moved via a heat transfer medium (air or water) that is part of the distribution and delivery subsystems. Controls make the whole thing work well. the focus herein is on active systems, with dedicated-purpose components Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 7 Example: Air-Based Collector outlet duct inlet duct flat plate collector, fixed, used for space heating Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 8 4

5 Air Collector System Schematic solar radiation is captured and converted to heat in a collector then conveyed via hot air (in ductwork) to storage in a masonry mass (rock bed) and then delivered where the heat is needed cooler air returns to the collector to be reheated, and the cycle continues supply air return air Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 9 Air Collector System Diagram source controls distribution backup source storage delivery Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 10 5

6 Backup? Storage? The backup heat source shown in the previous schematic is a necessary part of a solar thermal heating system if space conditions need to be maintained under any and all weather conditions. This adds to the first cost of the system (the system has both solar-source and conventional-source components). The need for such a backup should be carefully considered. The basic elements of a solar heating system (source, distribution, delivery, control) are common to all heating systems. Storage, an additional element (and expense), is required to deal with the variable and cyclical nature of the energy source (the sun). It is very difficult to eliminate thermal storage. a first-cost analysis will seldom favor active solar thermal; a life-cycle cost analysis may often favor active solar thermal Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 11 Example: Water-Based Collector housing fluid outlet fluid channels (tubing) insulation glazing (aperture) it was that way when I found it collector surface (absorber) flat plate collector, fixed, use not obvious (could be space heating or domestic hot water) Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 12 6

7 Water Collector System Schematic solar radiation is captured and converted to heat in a collector then conveyed via hot water to storage in a tank; a heat exchanger (radiator, etc.) is needed to get heating effect into the room as with an air system, the water flows in a cyclical (but always closed) loop Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 13 Water Collector System Diagram showing common elements of source, distribution, and delivery plus storage and a backup source typical of a solar system (controls would also be provided) Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 14 7

8 Example: Solar Hot Water Storage one hopes (aesthetically) that this is a retrofit installation; but in any case storage tanks can be large especially in a residential occupancy where times of greatest use (mornings and evenings) do not match time of greatest solar collection (daytime) Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 15 Example: Evacuated Tube Collectors this type of collector provides some concentration, has low losses, high efficiency Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 16 8

9 Example: Custom Collector the collector serves as roofing and structure (for a mechanical room) aperture area = absorber area this is the definition of a flat plate collector Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 17 Library, Los Alamos National Lab a quite large flat plate solar collector array, integrated into a building using custom collectors (see previous slide) Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 18 9

10 Los Alamos Solar System underside of collectors is roof of mechanical room; darker yellow elements are fluid headers close-up of collector edge showing dust/leakage Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 19 Active Solar Aesthetics space heating systems Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 20 10

11 Building-Scale Tracking, Concentrating Collectors axis of rotation faceted (Fresnel) lens concentrates direct solar radiation onto absorber tube absorber tube (contains water) Fresnel lens concentrating and tracking collector (one-axis tracking; only the orientation changes), used for space cooling and space heating part of a large roof-mounted array Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 21 District-Scale Tracking, Concentrating Collectors axis of rotation test installation, Sandia national Labs concentrating and tracking collector, with one axis tracking (the tilt changes) Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 22 11

12 District-Scale Tracking, Concentrating Collectors municipal power generation, Australian outback parabolic concentrating and tracking collectors (two axis tracking) Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 23 Concentrating Solar Power (CSP) Collector Array flat, concentrating and tracking (two axis) solar collectors with tower receiver; used for commercial electricity production power tower with heliostats, Sandia (NM) Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 24 12

13 Active Solar Aesthetics one of the first actively solar heated buildings in the US; collector panels are actually refrigerator coil panels Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 25 Active Solar Aesthetics domestic hot water heating Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 26 13

14 Active Solar Collector Efficiencies solarprofessional.com note relative efficiency of various collector types; note drop off of efficiency with difference in fluid versus ambient temperature; compare these efficiencies to PV modules (next topic) Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 27 the DOE Solar Decathlon as a Showcase of Solar Homes Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 28 14

15 2005 Solar Decathlon Entries all 2005 entries (buildings) had both solar thermal and PV collectors; consider the aesthetics of the various building designs and integrations all 2005 images from USDOE WWW site: Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 29 Cal Poly San Luis Obispo Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 30 15

16 Concordia and Universite de Montreal Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 31 University of Colorado Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 32 16

17 Cornell University Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 33 Crowder College Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 34 17

18 Florida International Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 35 New York Institute of Technology Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 36 18

19 Pittsburgh Synergy Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 37 Rhode Island School of Design Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 38 19

20 Universidad de Madrid Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 39 Universidad de Puerto Rico Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 40 20

21 University of Maryland Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 41 University of Massachusetts Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 42 21

22 University of Michigan Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 43 Rolla (Missouri) Consortium Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 44 22

23 University of Texas at Austin Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 45 Virginia Tech Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 46 23

24 Washington State University Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik Solar Decathlon: Illinois Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 48 24

25 2009 Solar Decathlon: Illinois Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik Solar Decathlon: Germany Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 50 25

26 2009 Solar Decathlon: Germany Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik Solar Decathlon: Cornell Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 52 26

27 2009 Solar Decathlon: Cornell Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 53 End note A cat sunning himself in the doorway of a barn knows all about solar energy. Why can t man learn? E.B. White As quoted in The Return of the Solar Cat Book Ball State Architecture ENVIRONMENTAL SYSTEMS 2 Grondzik 54 27