Solar Energy Technology for Commercial Facilities John Archibald American Solar, Inc. Association of Energy Engineers Baltimore Chapter March 2002

What do solar energy systems offer? Energy savings Cost savings Reduced maintenance Improved reliability Improved operability Improved environment for workforce

What types of solar energy systems are available? Solar Electric –Photovoltaics (Electricity from solar cells) –Solar thermal electric (Focussed heat for steam turbine electricity) Active Thermal Systems pump air or water –Air heating up to 190 deg.F –Mid temperature water heating deg.F –Low temperature pool heating < 110 deg. F Passive Thermal Systems heat without fans or pumps

Where should solar electric systems be deployed? Photovoltaics –Remote applications with complex fuel/electricity delivery –Small local applications with high cost power line installation –Security lighting, sensors, and radio/call boxes –Lighting for critical operations Solar Thermal Electric –High cost electricity with concurrent heating needs –Combined heating, absorption cooling, and power applications –Energy Savings Performance Contracts for solar heat

Where should water heating systems be deployed? Mid temperature water heating –Displace high cost electric resistance domestic water heating –Large volume water preheating for labs, medical, or equipment washdown –Water tube radiant floor space heating Swimming pool heating –Almost all heated outdoor pools –Heated indoor pools without heat recovery from dehumidification –Heated indoor pools with high cost electric dehumidification

Where should solar air heating systems be deployed? Low temperature air - less than 110 deg.F –Ventilation preheating in cold climates –High volume low temperature drying applications Mid temperature air deg.F –Emergency generator standby heating all climates –Boiler air pre-heating all climates –Ventilation air heating and preheating –Heat pump pre-heating –Hot water heating with air to water heat exchanger –Air radiant floor and under floor ventilation

What makes a good solar application? Year round load, year round load, year round load –Make the system repay investment every day the sun shines Don’t try to make solar meet 100% of the peak energy needs for large systems –Use solar to cut “annual” costs of large energy systems Displace electric, propane, oil heat with solar heat Avoid conversion from the original solar energy for use or storage –no AC inverter, no batteries, no thermal storage tank, no grid connection

What makes a good solar application? Low installed cost –under $25/sq ft High solar efficiency –10 to 30 units of solar energy gathered for every unit of energy used to run fans or pumps –greater than 20% of available solar energy converted to heat or electricity Building integrated –makes building walls or roof do double duty (weather envelope and energy production) for no extra cost Buy the energy not the system, if capital funds are not available but operating funds for energy bills are

Standby heating of emergency generators Electric heaters keep engine jacket water at 130 deg F all year 2-8 KW typical load Solar heated air floods generator enclosure, reduces electric heating Warm air keeps engine ready to start Payback period well under 10 years ‘Free’ storage building New Federal Application

Solar energy looks better and does more than ever before! New aesthetics with building integrated technologies –New solar roofs –New solar walls New solar applications –EDGs, boiler air, heat pump preheat, ventilation air Lower installed costs Higher energy delivery Attractive economics