Solar Absorption Cooling

Efficient Use of Solar Energy

• Passive solar design of buildings with efficient
daylighting.
• Low temperature non-concentrating collectors for
low temperature end-use such as pool heating, hot
water, and space heating.
• Medium temperature moderately concentrating
collectors for thermo GS heat pump HVAC, 2E
absorption cooling, and process heat.
• High temperature concentrating tracking collectors
for CHP and process heat.
• High temperature concentrating tracking collectors
and PV for electric power production.

Wagner Project Specifications

• NYSERDA primary funding, $2.9M (2002 dollars)
• 320-ton Carrier hot water fired 1E absorption chiller
• 800 Sunmaster evacuated tube collectors with CPC
reflectors, 11,000 ft2 aperture, mounted on 22,000 ft2
platform
• 1900F - 2200F solar operating temperatures
• Medium temperature backup hot water boilers
• Provided heating/cooling/service hot water to two
campus buildings with 75,000 ft2 of floor area.
• Solar energy system averaged 55 man-hours per

Austin TX 30-Ton Solar 1E-Absorption Chiller,
2003

• 360 m2 aperture area of 180 ground-mounted Non-
Evacuated CPC collectors, 720 m2 gross horizontal
area
• Orientation: South, 200 slope
• Water HTF, 36 gpm, 520 Mbtu/hr peak output at
950C, filled system, over-temperature protected
• 2500 gallon SS pressurized thermal storage tank
• 30-ton Yazaki hot water fired 1E absorption chiller
• 13,000 ft2 pre-engineered steel single-story building
used for Austin Energy Sand Hill power plant
control center.

Solar Absorption vs Electric Chillers

• Accounting for the electrical grid energy losses,
the adjusted primary source fuel COP for electric
A/C units varies from 0.83 to 1.93, with an
average of 0.98.
• A hybrid solar/fuel 2E absorption chiller system
can produce an average cooling season solar
fraction of at least 60%, so that the net primary
source fuel COP is 3.0.
• Solar/fuel 2E absorption chiller systems will
consume one-third the average primary source
energy used for electric A/C in the US.

Sacramento, CA 20-Ton Solar 2-E Absorption HVAC
System, CEC Primary Funding, 1997

• 336 ICPC parallel collector tubes in three rows, filled
system, over-temperature protected
• 111 m2 Aperture Area, 156 m2 Gross Area, 186 m2
footprint
• Orientation South, Sloped at 280 (Latitude - 100)
• Water HTF, 40 gpm, 50 feet of water pressure drop, 220
Mbtu/hr peak heat output, 1770C maximum
• 1000 gallon stainless steel pressurized thermal storage tank
• 20-ton Sanyo-McQuay direct-fired 2E absorption chiller
modified to hot water fired at 1650C with tube-in-shell,
reverse-flow generator
• 8,000 ft2 single-story building used for print shop and
offices

ICPC Collector Highlights

• Evacuated Borosilicate glass tube with proprietary
non-imaging optics reflector inside.
• Proprietary selective coating on stainless steel
absorber tube with absorptivity ~98% and emissivity.
~6% over wide temperature range.
• Ten-tube modules anticipated.
• Vertical load of 6.7 lb/ft2.
• Flexible roof-mounting requirements.

Solar Energy System Highlights

• Roof-mounted ICPC evacuated tube collectors reduce
solar gain and reduce building cooling load.
• Approximately 50% of collectable solar energy
delivered to 2E absorption chiller at 3300F.
• Peak cooling energy per peak collectable solar energy
equals 60%.
• Non-tracking.
• Low maintenance and long life.
• Any suitable clean backup fuel including biofuels.
• 2E absorption chiller: high reliability, environmentally
friendly, average maintenance costs, full automatic
operation.
• System-ready for organic Rankine cycle (ORC) enginegenerator
when such equipment is available (30kW per
100 tons).
• Energy peak shaving.
• Insurance against rising energy costs.
• Summer: 100 tons of cooling and domestic hot
water heating.
• Winter: space and domestic hot water heating.
• Emissions annual reductions:
CO2 = 182,000 lb SO2 = 170 lb NOx = 240 lb

Dual Energy Source Absorption Chiller-
Heater

• Absorption chiller can be fired by natural gas,
LPG, fuel oil, hot water, steam, or hot thermal oil
• Newest units provide 1800F hot water for heating.
• Eliminates the need for separate backup energy
source for solar absorption HVAC system
• Lower capital costs and higher system efficiency
• Concept fully tested in 50-ton Yazaki 2E chiller
• Patent issued in 2006.
• Broad Air Conditioning Co. is now manufacturing
dual energy source 2E absorption chillers.