Solar Thermal: Water Heating and Beyond

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1 Solar Thermal: Water Heating and Beyond Space Cooling Domestic Hot Water Energy Efficient Buildings Pool Heating Space Heating Jane Davidson University of Minnesota Tim Merrigan, Jay Burch National Renewable Energy Laboratory

2 Residential Energy Use Q tot,avg ~ 200 GJ primary The Big 3-Thermal loads: 55% of total, 2.34 TWh H 2 O Heat Cool Space Htg Space Clg Water Htg Lighting Refrigeration Electronics Other

3 World Market for Solar Thermal Heat ) Solar Heating: More installed capacity than ALL other renewables; production ~1/3 all renewable energy

4 US Solar Hot Water Market Israel 8 % ROW 7 % Japan 3 % Europe 17 % China 65 % Germany, Greece and Austria are the three largest markets in Europe, with a combined installed solar thermal area of 9.6 million m 2. Austria (8 million people) has an installed solar thermal capacity of 1.5 GWth, equal to that of the installed solar thermal capacity in the US (300 million people).

5 Potential Energy Savings (kwh) Energy saved using a glycol solar system with a selective surface collector Source: Danny Parker, FSEC

6 Current Economics of SDHW The cost required to attain cost-neutrality with electricity

7 SWH in the U.S. Current technology is not cost effective Except sunny places against electricity Small Industry Continued low volume (~20,000 systems/year) No established installers in many areas Sustained R&D with vision for short and long-term advances required

8 U.S. R&D Low-Cost Solar Hot Water Paradigm shift from metal/glass components to integrated systems manufactured with polymeric materials Successful project outcomes are a major step toward lower cost Building integrated systems FAFCO polymer collector

9 Example: FAFCO Revolution and Hot 2 O Introduced at National Association of Homebuilders (NAHB) International Builders Show, 2007 SRCC OG-300 Everything is in one box Polymer collectors (48 ft 2 ) Digital controller with animated display 80 Feet of UV resistant polymer tubing and quick connect fittings Polymer drain back tank Circulation module containing two pumps and a heat exchanger Roof jacks and mounting hardware Easy to install tank adapter and all plumbing hardware

10 MJ Solar Thermal 26% Space Conditioning 13% Heat Solar H 2 O Cool One technical challenges is long term, compact thermal storage.

11 Desired Material Characteristics Energy density [kwh/m 3, MJ/m 3 ] incls. tank, HX Operating temperatures charge/discharge Thermal power [W] charge/discharge Storage period Material stability Environmentally safe Non-toxic Non corrosive Available and inexpensive

12 Desired Material Characteristics Energy density [kwh/m 3, MJ/m 3 ] incls. tank, HX Operating temperatures charge/discharge Thermal power [W] charge/discharge Storage period Material stability Environmentally safe Non-toxic Non corrosive Available and inexpensive From IEA Task 32 Hadorn, 2008

13 Heating of school in Munich, Germany built by ZAE Bayern Diurnal storage of heat from district heating at 130 ºC Storage in 700 kg Zeolite (volume 10 m 3 ) 450KJ/m 3-3X capacity of water A/C of adjacent Jazz club in summer

14 Combined Solar Heating, Cooling, and Water Heating System Absorption airconditioner Space Cooling Solar collectors Heat Weak Desiccant Strong Desiccant Desiccant and water thermal storage Heat Heat Absorption heat pump Under development at NREL/University of Minnesota

15 Solar Thermal Opportunities Near term potential to reach a $1000 solar water heater Mid-term Opportunity: Open up space conditioning Europeans and other countries are seeking these opportunities to address future market needs --- U.S. should do the same or better!

16 Contact Info: Jane Davidson Department of Mechanical Engineering University of Minnesota Tim Merrigan Jay Burch National Renewable Energy Laboratory Golden, CO