Presentation on theme: "ELTR 1223 Survey of Renewable Energy Technology Overview of Solar Thermal Applications Unit 5 Source:"— Presentation transcript:
ELTR 1223 Survey of Renewable Energy Technology Overview of Solar Thermal Applications Unit 5 Source:
Use Policy This material was developed by Timothy J. Wilhelm, P.E., Kankakee Community College, with funding from the National Science Foundation as part of ATE Grant No. 0802786. All materials in this presentation are designed and intended for educational use, only. They may not be used for any publication or commercial purposes. Source:
Author, Editors/Reviewers Author: Timothy J. Wilhelm, P.E., Kankakee Community College Editors/Reviewers / Modifier: Chris Miller Heartland Community College Source:
Objectives Students will be able to describe, in very simple terms, black body absorption and radiation and their relationship to solar thermal applications. Students will be able to list the basic residential applications for solar thermal technology. Source:
Objectives Students will be able to discuss the basic requirements for passive solar architectural design. Students will be able to discuss and describe how active solar thermal technology works. Source:
Thermal Applications = Using Heat Typical Thermal Applications in Daily Human Living – Residential Dwelling Applications: Space Heating Water Heating Cooking
Contemporary Thermal Sources The Heat Energy Necessary for Space Heating, Water Heating, and Cooking is typically Converted from: – Electricity – Natural Gas – LPG – Fuel Oil – Coal – Wood – Other Combustible Fuels
Challenges Regarding our Conventional Sources of Thermal Energy Limited, Finite Supply All (except nuclear-fission sourced electricity) pump CO 2 back into the atmosphere All result in one or more additional, environmental pollutants The cost of all is continually increasing Most are not locally available and must be transported in
Moving Heat Energy to Where We Need it… Heat is directed and moved via… IR Radiation Conduction Convection
Conduction, Convection, and Radiation Source: http://cobblearning.net/rlimpert/files/2010/02/a3a421b29aedfa72.jpg
The Sun as a Source of Thermal Energy Black Body radiation and absorption! We see only reflected light When we see white light, the white surface is reflecting all frequencies of visible light When we see red light, the red surface is only reflecting the red frequency of visible light, and is absorbing all the other frequencies of visible light When a surface appears black it is absorbing all the frequencies of visible light and reflecting none
Black Body Radiation and Absorption Black Bodies absorb ALL frequencies At temps below 200 o C, Black Bodies (all bodies) radiate InfraRed frequencies InfraRed radiation is HEAT! Source: http://www.popsci.com/files/imagecache/article_image_large/files/articles/colorfire_485.jpg
Solar Thermal Technologies The basic ideas behind solar thermal energy are: – Convert solar radiation into heat energy via Black Body absorption – Trap the captured heat energy Limit IR radiation losses Limit Convective losses Limit Conductive losses – Direct the captured heat energy into the desired zone or material via IR radiation, and/or convection, and/or conduction
Solar Thermal Technologies Solar Space Heating vs. Solar Domestic Hot Water Heating vs. Solar Cooking Passive vs. Active Solar Thermal Applications Flat Plate Solar Collectors vs. Concentrating Solar Collectors
Solar Space Heating Passive Solar Principles: Insulate, insulate, insulate (especially the North wall) Orient long axis of building E-W Lots of South facing glazing Thermal storage Nocturnal insulation on South wall Summer shading to avoid seasonal over heating
Passive Solar Principles Source: http://www.energysavers.gov/images/five_elements_passive.gif
Passive Solar Principles Source: http://www.solarbuildings.ca/c/sbn/img_db/alstonvale.JPG
Passive Solar Principles Source: http://knowledgepublications.com/heat/images/Solar_Air_Window_Box_Collectors.gif
Active Solar Space Heating Principles Same as Passive principles, but… Add on external solar collectors Add on fans or pumps to move fluid Air or water or other FLUID Different configurations of heat storage May incorporate heat pumps May be flat-plate or concentrating
Active-Solar Space Heating with Liquid Working Fluids Source: http://www.solarage.co.uk/res/embedded/swhsystem.gif
Solar Domestic Hot Water Heating Can be active or passive (thermo-siphon) Can be open loop – Open loop can be drain-down configured for freeze protection Can be closed loop – Closed loop can be drain-back configured for freeze protection – Closed loop can be freeze protected by using antifreeze as the working fluid
Passive Solar DHW Heating Batch Tank Heating Thermo-siphon
Passive Solar Water Heating Batch heaters Source: http://www.byexample.com/library/photos/projects/batch_collector/bc_01697.jpg
Passive Solar Water Heating Thermo-siphon heaters Source: http://www.altensol.com.ph/?404=Y
TEI Patra: 3-18 July 2006 Intensive program: ICT tools in PV-systems Engineering Schematic diagram of a thermosyphon solar water heater Auxiliary Storage tank Hot water outlet Cold water inlet
TEI Patra: 3-18 July 2006 Intensive program: ICT tools in PV-systems Engineering Laboratory model
TEI Patra: 3-18 July 2006 Intensive program: ICT tools in PV-systems Engineering Typical thermosyphon solar water heater
Active Solar DHW Heating System Design Governed by Need for System Efficiency and Freeze Protection
Active Solar Water Heating Source: http://www.amecosolar.com/waterheat.jpg
What type of system would I use in my area? Warm climates systems similar to those shown previously systems will differ in design Cold climates freeze protection becomes critical Indirect systems with heat exchangers Drainback and draindown systems
Warm climates Fluid in tank is heated in collector Most common system in temperate climates
Warm climates This system is called a thermosiphon system. It does not have pumps, controllers, or any moving parts. Water is heated and the density of the hot versus cold water takes over from there. Works off natural thermosiphon actions in moving the water heated in the collector back to the tank and the cold water in the tank to the collector.
TEI Patra: 3-18 July 2006 Intensive program: ICT tools in PV-systems Engineering Direct circulation system
Cold climates Indirect system with heat exchanger that contains fluids in collector that do not freeze. Heat exchanger is in the water heater.
TEI Patra: 3-18 July 2006 Intensive program: ICT tools in PV-systems Engineering Drain-down system When a freezing condition or a power failure occurs, the system drains automatically by isolating the collector array and exterior piping from the make-up water supply and draining it using the two normally open (NO) valves
TEI Patra: 3-18 July 2006 Intensive program: ICT tools in PV-systems Engineering Indirect water heating system
TEI Patra: 3-18 July 2006 Intensive program: ICT tools in PV-systems Engineering Drain-back system Circulation continues as long as usable energy is available. When the circulation pump stops the collector fluid drains by gravity to a drain-back tank.
Cold climates Indirect system with heat exchanger that contains fluids in collector that do not freeze. Heat exchanger is external to the water heater.
Cold climates Drainback system In this system all the water in the collector drains back into a reservoir.
Cold climates In this system, all the water in the collectors drains out of the collector. Draindown system.
Cold climate Another thermosiphon system similar to the one used in warm climates, but this one has a heat exchanger incorporated in the system to protect the collector during freezes. Source: http://mashav.com/solar-energy/sirt.jpg
Stationary Collectors for DHW Flat Plate Collectors Paint or Selective Surface Evacuated Tube Collectors
TEI Patra: 3-18 July 2006 Intensive program: ICT tools in PV-systems Engineering Flat-plate collector
TEI Patra: 3-18 July 2006 Intensive program: ICT tools in PV-systems Engineering Flat-plate Collectors
TEI Patra: 3-18 July 2006 Intensive program: ICT tools in PV-systems Engineering Types of flat-plate collectors Water systems Glazing Riser Absorbing plate Insulation A B Glazing Riser Absorbing plate Insulation C Glazing Riser Absorbing plate Insulation D Glazing Riser Absorbing plate Insulation
TEI Patra: 3-18 July 2006 Intensive program: ICT tools in PV-systems Engineering Schematic diagram of an evacuated tube collector
TEI Patra: 3-18 July 2006 Intensive program: ICT tools in PV-systems Engineering Evacuated tube collectors Source: http://www.lightheat.com/home_heating/images/the rmomax3.jpg
TEI Patra: 3-18 July 2006 Intensive program: ICT tools in PV-systems Engineering Swimming pool heating -- Another water heating application Source: http://build-it.hit.bg/solar.html
Parabolic Solar Concentrators Reflective Imaging Concentrators Specially-shaped, highly polished surfaces that reflects light rays, focusing them to a very sharp point on the light-source-side of the reflector…MANY more W/m 2 into a VERY small mass or space = MUCH higher temperatures. These are all based on the geometry of the parabola. Line focused = HOT…single-axis tracking required Point focused = HOTTER…dual-axis tracking required
Solar-Thermal Process-Heat Applications Solar cooking High temperature boilers for steam engines Low temperature boilers for ORC engines Stirling-cycle external combustion heat engines The Minto Wheel …and, MORE
Solar Cooking – Non-imaging Source: http://www.builditsolar.com/Projects/Cooking/BillsPage.jpg
Solar Cooking -- Imaging Source: http://wohnen.pege.org/2005-afrika/solarkocher.jpg
Solar Cooking, Single Hot Dog Scale Source: http://westernpower.com.au/pluginkids/
Design Problem Commercial-size Solar Greenhouse Challenges: Maximum sunlight means minimum structure They typically melt off the snow load! Nocturnal insulation in a 2,000 square foot building? Thermal storage? What would you do?