SolarWall® Air Heating and Ventilation Systems

SolarWall® system at GoodYear Tires.

The SolarWall® technology delivers one of the verifiably fastest solar paybacks. The system

uses the sun’s energy to pre-heat ventilation air for commercial,

industrial, institutional, multi-residential and agricultural buildings, as well as for crop and

process drying applications.  It substantially reduces traditional heating fuel expenses in a

building integrated system which requires no maintenance and has a 30+ year lifespan. The

SolarWall system also acts as a rain screen, and we now offer our new SolarWall 2-Stage

System that offers even higher performance solar air heating.

 

Independent monitoring data indicates that SolarWall systems can displace between 20-

50% of heating fuel consumption, depending on size and application.

 

Owens Corning was awarded the 2010 Solar Thermal Project of the year award by the

Canadian Solar Industries Association for generating 3600 MWh of solar energy and

displacing over 600 tons of CO2/year with their 18,000 ft2SolarWall® system.

Heating can typically be one of the largest energy expenditures in the building industry. 

The ability of a SolarWall system to address this energy usage and to displace a sizable

amount of it - and the resulting greenhouse gas emissions - explains why the technology

has such a compelling return on investment, and why "from an operational point of view, [it]

is the greatest technology in the world." (Quote from Desmond Raymond, Parks Canada)

 

In the late 1970s, Conserval Engineering began developing methods to reduce energy

consumption in industrial and commercial applications. By the 1990s, the company had

invented one of the world’s most efficient ways to harness the sun’s energy to help heat

buildings of all shapes, sizes and functions – new or retrofit. The product’s apt name: The

SolarWall® system.

 

Worldwide interest was sparked immediately, and the ingenuity of the SolarWall technology

was recognized by organizations such as the U.S. Department of Energy, Natural Resources

Canada, Popular Science Magazine, R&D Magazine, and several others.

 

3M Canada's  SolarWall® system at their Perth Ontario location.

The SolarWall technology has lead the way ever since in defining the global solar air heating

industry, both scientifically and in world-wide applications, with customers such as Ford

Motor Company, 3M, Prologis, GM, Toyota, FedEx, Bombardier, the U.S. Military, and many

more in over 30 countries. The high level of architectural versatility, combined with

substantial energy savings and LEED point generation, have made it a popular renewable

energy technology for building owners, facility managers and architects.

 

"[SolarWall is in the] top two percent of energy related inventions."

How the SolarWall® Technology Provides Fresh Air & Free Heat

Product description: The SolarWall® solar air heating system

The SolarWall® air heating system is a custom engineered solution containing many

internal and external components. It uses solar energy to heat and ventilate indoor spaces

in new and retrofit applications, as well as to heat air for manufacturing process and

agricultural crop drying applications. The system design is optimized to maximize energy

delivery with a minimum amount of static pressure in the airflow.

The most visible component of the system tends to be the exterior metal “solar cladding”;

however a significant amount of the science behind SolarWall is in the internal framing

design and component shapes.  Special vent-slit perforated collector panels are installed

several inches from a south facing wall, creating an air cavity. (Southeast, southwest, east,

and west wall are also possible.) The SolarWall cladding (transpired solar collector) is heated

by the solar radiation from the sun, and ventilation fans create negative pressure in the air

cavity, drawing in the solar heated air through the exterior panel perforations. The

proprietary manufacturing equipment and design process - for both the panels and the

framing system - are used to control the amount of airflow through the perforations. This

maintains a consistent draw across the entire wall surface and ensures the cooler air

beyond the heated boundary layer is not introduced into the air stream.

The air is generally taken off the top of the wall (since hot air rises) and that ensures that all

of the solar heat produced is collected. The heated air is then ducted into the building via a

connection to the HVAC intake. On a sunny day, the air entering the air handling unit will

already be heated – anywhere from 30-70°F (16-38°C) for a conventional SolarWall system

and 36-100°F (20-55°C) for a 2-Stage SolarWall system.  This reduces, or may even

eliminate, the conventional heating load during the day.  The solar heated fresh air is then

distributed into the building through the existing HVAC system or with separate air makeup

fans and perforated ducting.

There are many variations to the SolarWall technology, based on a building's energy

requirements or a customer's objectives. Examples include conventional single-stage

SolarWall systems that can be styled, shaped and angled in a variety of colors; 2-Stage

SolarWall systems for higher temperature rises; and rooftop SolarDuct® systems (these are

usually 2-Stage systems to deliver higher temperature rises).

SolarWall Schematic Diagrams

2-Stage SolarDuct2-Stage SolarWall

SolarWall Interior Fan SolarWall Rooftop HVAC

As well as providing on-site renewable energy, the SolarWall® technology is also commonly

specified when increased ventilation air is required, or for building remediation purposes

when exterior cladding has to be replaced. In retrofit applications, SolarWall systems are

one of the few technologies that can be: a) easily integrated into an existing building, and b)

cost-effective in reducing a large amount of energy. A SolarWall system also acts as a rain

screen.

The SolarWall technology can also make an excellent addition to a HRV (Heat Recovery

Ventilator) systemby preheating the incoming ventilation air and increasing the system

efficiency.

Overall, decades of research and field experience ensures that whatever the design

considerations may be, the SolarWall system will perform at an optimal efficiency.

Performance and Economics

The performance of the SolarWall technologies have been established through

extensive testing and third party monitoring by organizations such as the U.S.

Department of Energy’s National Renewable Energy Laboratory (NREL), Natural

Resources Canada, and numerous others in countries around the world. This

independent third party verification has substantiated the energy savings that the

SolarWall systems deliver.

The SolarWall technology provides free heat for the life of the building

Delivers air temperature rises of 30-100°F (16-55°C) above ambient depending on

flow rate

Generates annual CO2 savings of 1 ton for each 5 square meters (50 square feet) of

collector

It reduces annual heating costs by $2 - $8 per square foot ($20-$80 per square

meter) of collector, depending on the type and cost of fuel displaced

It delivers ventilation air that can represent up to 50% of a building’s heating energy

needs

Contributes 1.5 – 3.5 therms/ft2 (1.5 – 3.5 GJ/m2) of energy per year

High solar efficiency (up to 80%)

SolarWall systems are comparable to the cost of a brick wall, and the total installed

cost after tax considerations and possible grants can mean a SolarWall system may

be less expensive than other metal or masonry wall options

Even on cloudy days, the system provides significant energy savings as a preheating

system for ventilation air

Lowers summer cooling costs by shading the inner wall from direct sunlight

Maintenance free over its 40+ year lifespan

 

 

Typical SolarWall Construction

    

1-SolarWall panels on typical block wall construction 2-SolarWall panels on typical metal wall construction

 

SolarWall 2-Stage - High Performance Solar Air Heating

View the record-breaking temperatures rises of 36-100 °F ( 20-55 °C) above

ambient being delivered from recent SolarWall 2-Stage installations!

 

Up to 50%+ More Thermal Energy

Independent testing and field applications have

shown that SolarWall 2-Stage will deliver up to

50+% more energy than a conventional

SolarWall system, with temperature rises over

100°F being achieved on a regular basis.

The SolarWall® air heating technology has

always generated an impressive economic

return for commercial & industrial buildings due

to its high efficiency & low capital costs.  It has

been primarily used for ventilation heating or

process applications, with a consistent track-

record of delivering high energy performance in

all projects around the world.

SolarWall® 2-Stage is the latest version of the SolarWall® technology and it builds on the

technological success of the original solar air heating system.  SolarWall® 2-Stage has been

configured to deliver a higher temperature rise – up to36-100 °F ( 20-55 °C) above ambient

temperature.  It is also ideally suited for windy locations and roof-mount projects. [And as

the wind speed increases, the energy output of the 2-stage system will continue to increase

relative to the conventional SolarWall system.] It operates on the same premise as the

original SolarWall® technology in that outside air is heated and drawn into an air cavity via

tiny mirco-perforations in the SolarWall collector.  With the 2-Stage system, the air is then

heated a second time (which boosts the temperature rise) as it passes though a second

stage of the system.  The solar heated air is then directed into the building’s ventilation

system - or through a dedicated SolarWall fan & ducting system - where it is distributed

throughout the building.

Features & Advantages

Higher energy output that substantially

lowers heating bills

Delivers significantly more thermal energy (as much as 50%) than a conventional

low-flow SolarWall® system

Heats air 36-100 ˚F (20-55 ˚C) above ambient on a sunny day

Maintenance free

Up to 10+ LEED® Points

Heats fresh air and improves indoor air quality

Destratification savings for industrial buildings

Provides both space heating & ventilation air heating

Huge reduction in CO2 emissions

Building integrated - variety of colours

 

 

Defense Logistics Agency -

7-Eleven Store - Japan Agassiz Elementary School

- Agassiz BC

PA Eielson Air Force Base -

Alaska

Foley Catholic School -

Ontario Fort Drum - NY Fort MCCoy - Wisconsin

Plattsburgh International

Airport 2 Walls - New York

Plattsburgh International

Airport Roof - New YorkPortsmouth Naval Station -

Maine

Process Drying Leather -

Mexico

Yonge Street Mission,

Genesis Place Homes -

Toronto

Featured SolarWall 2-Stage Case Study:

 Plattsburgh International Airporttype: pdf | size: 202 kB

Location: Plattsburgh, New York

Project Completed: 2011

Summary: The SolarWall® 2-Stage system uses the standard unglazed

SolarWall for the lower portion of the wall, with the top SolarWall portion of the

unit (2nd stage) covered by polycarbonate glazing.  It is attached to the walls by

framing materials, which are spaced to provide optimized channels for air flow between

the SolarWall and the wall.

SolarDuct® Modular Rooftop Solar Air Heating System

SolarDuct® is based on the highly efficient and award-winning SolarWall® system. The

technology has been specifically engineered for roof settings and for applications in which a

traditional wall mounted system is not feasible.

Like the original SolarWall® technology, SolarDuct® is a solar heating system that heats

ventilation air before it enters the air handling units. The patented system uses an all-metal

collector panel (transpired solar collector) and is suitable for commercial, industrial, and

institutional facilities. Perforations in the panels allow the heat that normally collects on a

dark surface to be uniformly drawn

through the SolarDuct® panel and then ducted into the conventional HVAC system.

The SolarDuct® system is optimized to meet site conditions in terms of orientation towards

the sun and proximity to rooftop air handling units. The modular arrays are sized according

to the energy requirements of the building.

SolarDuct® Features & Advantages

Heats ventilation air using the highest

performing and lowest cost solar collector on

the market

Collector efficiency up to 80%

Easy to install modular rooftop units

Optimized to meet site conditions

Internally ballasted or fastened system which is

quick to assemble and simple to integrate into

existing air intake system

Individual units are 6’ by 4’ and each produces 1000 watts of thermal energy

Typical string length is 48 feet long (8 units) with no limit to array size, and will

deliver up to 2000 CFM of heated ventilation air and 8kW of heating

Substantial CO2 displacement

 

Conserval Engineering Inc -

Toronto, Ontario

Joliet Junior College

Maintenance Building - IL

Kecskemet - Hungary

Mainland Commons -

Halifax

NRG - Winnipeg, Manitoba

Renault Dealership - SpainToyota Dealership - Spain

Western Oregon University

- Oregon

More Information on SolarDuct and SolarDuct PV/T

Below are SolarDuct leaflets that contain additional information on SolarDuct solar air

heating & the SolarDuct PV/T co-generation option. Download the PDF (requires a PDF

reader; e.g. Adobe Reader) or view online (requires Flash).

SolarWall® Make-up Air Fan and Ventilation Systems

Industrial buildings typically exhaust large quantities of air.

This air must be replaced, otherwise problems will occur such

as cold drafts around doors, reverse flows through gravity

vents and chimneys, and inefficient operation of mechanical

exhaust equipment.

The SolarWall fan system is a low cost method to remedy

these problems. It can:

reduce

heating costs

by utilizing

stratified heat

under the

ceiling

destratify

indoor air

temperatures

from ceiling to floor

permit exhaust systems to operate properly during the

heating season

eliminate cold drafts due to the infiltration of outdoor

air

prevent reverse flow through gravity vents and

chimneys

improve the operation of heating equipment

solve indoor air quality problem

Wall mounted SolarWall make-up air fan, with fabric duct

The unit consists of:

a fan unit

modulating

mixing

dampers

proportional

temperature

control

fan, dampers and controls all prewired for easy

installation

flame retardant fabric duct with precision jet openings

The ducting system:

eliminates blasts of air from air make-up units

improves air distribution

evens out cold and hot spots

saves energy and money

has a payback of less than one year

The SolarWall duct

system is flame

retardant perforated

polyethylene ducting

that can be easily

retrofitted to existing

or new air

equipment. It is hung

below a roof from a

steel cable using hooks and is available in many stock

diameters, and three different configurations. Each duct is

custom perforated and cut to length.

Winter mode is available for heated air make-up applications

with fixed air jet hole positions to mix outside air with the

stratified heat under the ceiling.

Summer cooling mode has holes pointing down to direct the

air onto the working floor. Summer/winter mode ducts have

supports on the top and bottom of the duct, allowing it to be

rotated 180o. This allows the duct to blow air downwards in

summer and upwards in winter.

SolarWall® Fan Unit Construction

FRAME Welded structural angle iron

CASING Prime galvanized steel 18 & 20 gauge

DAMPERS Extruded low leakage aluminum dampers mounted in bronze bushings

FAN Six bladed heavy-duty propeller

BEARINGS Self-aligning pillow blocks pre-lubricated

CONTROLS Automatic temperature control in control panel or remote

SolarWall 2-Stage - High Performance Solar Air Heating

View the record-breaking temperatures rises of 36-100 °F ( 20-55 °C) above

ambient being delivered from recent SolarWall 2-Stage installations!

 

Up to 50%+ More Thermal Energy

Independent testing and field applications have

shown that SolarWall 2-Stage will deliver up to

50+% more energy than a conventional

SolarWall system, with temperature rises over

100°F being achieved on a regular basis.

The SolarWall® air heating technology has

always generated an impressive economic

return for commercial & industrial buildings due

to its high efficiency & low capital costs.  It has

been primarily used for ventilation heating or

process applications, with a consistent track-

record of delivering high energy performance in

all projects around the world.

SolarWall® 2-Stage is the latest version of the SolarWall® technology and it builds on the

technological success of the original solar air heating system.  SolarWall® 2-Stage has been

configured to deliver a higher temperature rise – up to36-100 °F ( 20-55 °C) above ambient

temperature.  It is also ideally suited for windy locations and roof-mount projects. [And as

the wind speed increases, the energy output of the 2-stage system will continue to increase

relative to the conventional SolarWall system.] It operates on the same premise as the

original SolarWall® technology in that outside air is heated and drawn into an air cavity via

tiny mirco-perforations in the SolarWall collector.  With the 2-Stage system, the air is then

heated a second time (which boosts the temperature rise) as it passes though a second

stage of the system.  The solar heated air is then directed into the building’s ventilation

system - or through a dedicated SolarWall fan & ducting system - where it is distributed

throughout the building.

Features & Advantages

Higher energy output that substantially

lowers heating bills

Delivers significantly more thermal energy (as much as 50%) than a conventional

low-flow SolarWall® system

Heats air 36-100 ˚F (20-55 ˚C) above ambient on a sunny day

Maintenance free

Up to 10+ LEED® Points

Heats fresh air and improves indoor air quality

Destratification savings for industrial buildings

Provides both space heating & ventilation air heating

Huge reduction in CO2 emissions

Building integrated - variety of colours

 

 

Defense Logistics Agency -

7-Eleven Store - Japan Agassiz Elementary School

- Agassiz BC

PA Eielson Air Force Base -

Alaska

Foley Catholic School -

Ontario Fort Drum - NY Fort MCCoy - Wisconsin

Plattsburgh International

Airport 2 Walls - New York

Plattsburgh International

Airport Roof - New YorkPortsmouth Naval Station -

Maine

Process Drying Leather -

Mexico

Yonge Street Mission,

Genesis Place Homes -

Toronto

SolarWall® Make-up Air Fan and Ventilation Systems

Industrial buildings typically exhaust large quantities of air.

This air must be replaced, otherwise problems will occur such

as cold drafts around doors, reverse flows through gravity

vents and chimneys, and inefficient operation of mechanical

exhaust equipment.

The SolarWall fan system is a low cost method to remedy

these problems. It can:

reduce

heating costs

by utilizing

stratified heat

under the

ceiling

destratify indoor air temperatures from ceiling to floor

permit exhaust systems to operate properly during the

heating season

eliminate cold drafts due to the infiltration of outdoor

air

prevent reverse flow through gravity vents and

chimneys

improve the operation of heating equipment

solve indoor air quality problem

Wall mounted SolarWall make-up air fan, with fabric duct

The unit consists of:

a fan unit

modulating

mixing

dampers

proportional

temperature

control

fan, dampers and controls all prewired for easy

installation

flame retardant fabric duct with precision jet openings

The ducting system:

eliminates blasts of air from air make-up units

improves air distribution

evens out cold and hot spots

saves energy and money

has a payback of less than one year

The SolarWall duct

system is flame

retardant perforated

polyethylene ducting

that can be easily

retrofitted to existing

or new air

equipment. It is hung

below a roof from a

steel cable using hooks and is available in many stock

diameters, and three different configurations. Each duct is

custom perforated and cut to length.

Winter mode is available for heated air make-up applications

with fixed air jet hole positions to mix outside air with the

stratified heat under the ceiling.

Summer cooling mode has holes pointing down to direct the

air onto the working floor. Summer/winter mode ducts have

supports on the top and bottom of the duct, allowing it to be

rotated 180o. This allows the duct to blow air downwards in

summer and upwards in winter.

SolarWall 2-Stage - High Performance Solar Air Heating

View the record-breaking temperatures rises of 36-100 °F ( 20-55 °C) above

ambient being delivered from recent SolarWall 2-Stage installations!

 

Up to 50%+ More Thermal Energy

Independent testing and field applications have

shown that SolarWall 2-Stage will deliver up to

50+% more energy than a conventional

SolarWall system, with temperature rises over

100°F being achieved on a regular basis.

The SolarWall® air heating technology has

always generated an impressive economic

return for commercial & industrial buildings due

to its high efficiency & low capital costs.  It has

been primarily used for ventilation heating or

process applications, with a consistent track-

record of delivering high energy performance in

all projects around the world.

SolarWall® 2-Stage is the latest version of the

SolarWall® technology and it builds on the

technological success of the original solar air heating system.  SolarWall® 2-Stage has been

configured to deliver a higher temperature rise – up to36-100 °F ( 20-55 °C) above ambient

temperature.  It is also ideally suited for windy locations and roof-mount projects. [And as

the wind speed increases, the energy output of the 2-stage system will continue to increase

relative to the conventional SolarWall system.] It operates on the same premise as the

original SolarWall® technology in that outside air is heated and drawn into an air cavity via

tiny mirco-perforations in the SolarWall collector.  With the 2-Stage system, the air is then

heated a second time (which boosts the temperature rise) as it passes though a second

stage of the system.  The solar heated air is then directed into the building’s ventilation

system - or through a dedicated SolarWall fan & ducting system - where it is distributed

throughout the building.

Features & Advantages

Higher energy output that substantially

lowers heating bills

Delivers significantly more thermal

energy (as much as 50%) than a

conventional low-flow SolarWall®

system

Heats air 36-100 ˚F (20-55 ˚C) above

ambient on a sunny day

Maintenance free

Up to 10+ LEED® Points

Heats fresh air and improves indoor air quality

Destratification savings for industrial buildings

Provides both space heating & ventilation air heating

Huge reduction in CO2 emissions

Building integrated - variety of colours

 

 

7-Eleven Store - Japan Agassiz Elementary School

- Agassiz BC

Defense Logistics Agency -

PA Eielson Air Force Base -

Alaska

Foley Catholic School -

Ontario Fort Drum - NY Fort MCCoy - Wisconsin

Plattsburgh International

Airport 2 Walls - New York

Plattsburgh International

Airport Roof - New YorkPortsmouth Naval Station -

Maine

Process Drying Leather -

Mexico

Yonge Street Mission,

Genesis Place Homes -

Toronto

SolarDuct® Modular Rooftop Solar Air Heating System

SolarDuct® is based on the highly efficient and award-winning SolarWall® system. The

technology has been specifically engineered for roof settings and for applications in which a

traditional wall mounted system is not feasible.

Like the original SolarWall® technology, SolarDuct® is a solar heating system that heats

ventilation air before it enters the air handling units. The patented system uses an all-metal

collector panel (transpired solar collector) and is suitable for commercial, industrial, and

institutional facilities. Perforations in the panels allow the heat that normally collects on a

dark surface to be uniformly drawn

through the SolarDuct® panel and then ducted into the conventional HVAC system.

The SolarDuct® system is optimized to meet site conditions in terms of orientation towards

the sun and proximity to rooftop air handling units. The modular arrays are sized according

to the energy requirements of the building.

SolarDuct® Features & Advantages

Heats ventilation air using the highest

performing and lowest cost solar collector on

the market

Collector efficiency up to 80%

Easy to install modular rooftop units

Optimized to meet site conditions

Internally ballasted or fastened system which is

quick to assemble and simple to integrate into

existing air intake system

Individual units are 6’ by 4’ and each produces 1000 watts of thermal energy

Typical string length is 48 feet long (8 units) with no limit to array size, and will

deliver up to 2000 CFM of heated ventilation air and 8kW of heating

Substantial CO2 displacement

 

Conserval Engineering Inc -

Toronto, Ontario

Joliet Junior College

Maintenance Building - IL

Kecskemet - Hungary

Mainland Commons -

Halifax

NRG - Winnipeg, Manitoba Western Oregon University

Renault Dealership - Spain Toyota Dealership - Spain - Oregon

More Information on SolarDuct and SolarDuct PV/T

Below are SolarDuct leaflets that contain additional information on SolarDuct solar air

heating & the SolarDuct PV/T co-generation option. Download the PDF (requires a PDF

reader; e.g. Adobe Reader) or view online (requires Flash).

NightSolar® Solar Cooling System

The patented NightSolar® systems remove energy from the air to cool buildings without

the use of compressors or refrigeration systems.   This solar cooling technology is partly

based on the scientific principle of nocturnal radiation, which can cool a roof by as much as

10°C (18°F) below ambient temperature on a clear night. As warm night air touches the

cooler surface of the NightSolar® system, it transfers its heat to the surface, which cools

the air.  The chilled air is then drawn in through perforations in the collector and enters the

HVAC unit via an economizer cycle.  This cooling has the ability to reduce or even displace

conventional air conditioning from sunset to sunrise.  During the daytime, the NightSolar®

system keeps the roof in the dark and thereby reduces daytime heat gains normally

received through the roof.

Recent field monitored NightSolar® installations are reporting as much as a 50% overall

cooling savings on buildings using existing fans and economizers.

Features & Advantages

A NightSolar® system is an extremely versatile energy system that can be configured to

deliver a myriad of other benefits as well, including:

NightSolar®; The first commercially available solar cooling system that reduces the cooling

load on a building by up to 50%.

Solar space heating in the winter

Above sheathing ventilation (ASV) for both steep and low slope roofs

Virtually eliminates solar gain through roof

Significantly reduces the expansion and contraction issues that occur with a majority

of metal roofs

Optional integration with photovoltaics (PV)

Optional solar water heating

Rainwater catchment compatible

Extends roof life

 

Benefits of NightSolar® Ventilated Roof

NightSolar® systems utilize a ventilated roof design (also known as above-sheathing

ventilation) that is highly desirable for all buildings with metal roofs.  This reduces daytime

cooling by shading & ventilating the roof, meaning that unwanted solar heat is naturally

vented while drying any condensation that may have occurred on the roof.

Oak Ridge National Laboratory states "we serendipitously discovered the second major

advance in roofs for our century: We found that elevating the roof cover from the roof deck

to induce above-sheathing ventilation is as important as increasing solar reflectance and

may be the stronger player in reducing heat gain into the attic. The two combined can

reduce heat gain through the roof by 50% compared to nailed asphalt shingle roofs."

Solar Energy; 24/7

NighSolar® systems are unmatched in the realm of solar energy systems in that they can

be configured to offer solar energy generation and conventional energy displacement up to

24 hours a day, all year long.  This has been made possible because the solar collector

surface can be used for both cooling (in the warmer months) and also heating (in colder

months).  The end result to the building owner is substantial energy savings that occurs

from reducing on-site cooling and heating costs by up to 50%.  The system also qualifies for

the 30% federal solar tax credit.

The NightSolar system was developed by the inventors of the SolarWall® technology, and it

utilizes the same vent-slit-perforated collector that is used in the SolarWall® air heating

system. This allows for both summer space cooling and winter solar space heating. Storage

of heat and cold energy is also possible with separate thermal storage tanks via heat

exchangers.

PV/Thermal; Hybrid Solar Heating + Electricity

 

SolarWall® PV/T is a hybrid system which provides up to 300% more energy (in the form

of solar electricity + solar heat) than a conventional solar PV system.  The heat energy

captured from the PV modules is ducted into the building’s HVAC system where it is used to

displace the conventional heating load. The secondary benefit is to provide PV cooling by

reducing the operating temperature of the PV modules, which improves the electrical

performance.  Excess heat buildup behind PV panels is a common problem, and for every

1°C (1.8°F) above 25°C (77°F), the electrical output drops by 0.4 to 0.5 percent. Read more

here.

SolarWall® PV/T Value Proposition

Technology Watt / m2

PV Electrical Output100 Watts/m2

(10 Watts/ft2)

SolarWall® Thermal Output200-300 Watts/m2*

(20-30 Watts/ft2)

Hybrid SolarWall® PV/T300-400 Watts/m2

(30-40 Watts/ft2)

*SolarWall® system output when combined with PV

Note: SolarWall® output without PV is 500-600 Watts/m2

The hybrid PV/Thermal technology also produces the following additional benefits which

collectively help to accelerate the PV system return on investment:

System addresses the majority of a building’s energy requirements, which is both

heat and electricity

The hybrid PV/T system will have dramatically higher life cycle cost savings when

compared to a convention PV system because of the heat energy from the SolarWall

component.

The SolarWall thermal air panels replace the conventional racking system needed to

mount PV.

Huge reduction in greenhouse gas emissions.  Displacing the heating load is typically

a direct source reduction from CO2 because the fuel being displaced is usually natural

gas or heating oil.

Hedges against both electricity and heating costs

Also hedges against future legislation on renewable energy, GHG emissions, and

energy efficiency in the building sector

Allows for the production of two types of solar energy from one footprint

SolarDuct® PV/T

The technology is also available in a modular roof-top

configuration known as SolarDuct® PV/T. In this

application, the PV modules are mounted on top of the

SolarDuct units, and then heat is drawn off the back of

the PV modules and ducted to the nearest rooftop air

handling unit.  This “excess heat” is then channeled

into the building’s HVAC system where it offsets the

heating load.  Since the thermal heating panels do

“double-duty” by also acting as the PV racking system,

this also contributes to the cost-effectiveness of the hybrid system.  The modular units are

easy to install and are angled at an ideal orientation for maximum solar gain.

Capturing the Heat & PV Cooling

Above, SolarWall system at Natural Resources Canada's CANMET Buidling in Ottawa. The

SolarWall system was upgraded to a hybrid PV/T system in 2010, delivering both solar

heated air and electricity to the building.

Conserval Engineering originated the concept of combining PV with the SolarWall

technology. The objective was to address some of the problems inherent with conventional

photovoltaics, and to develop a solution that would further enhance PV as a viable

renewable energy solution for regular commercial and industrial buildings. Two problems

that can make PV unattractive are the lengthy payback periods and the low solar

efficiencies. The hybrid PV/T system provides a solution to both of these problems.

Typical PV modules have a solar conversion efficiency up to 15%. What happens to the rest

of the sun’s energy that shines on the panels? Most of it is converted into heat energy,

which normally is lost and provides no value to the system owner. As well, the heat build-up

behind PV modules reduces the electrical output by 0.4-0.5% for every 1°C above its rated

output temperature, which is 25°C (77°F). For every 1°C (1.8°F) above 25°C, the electrical

output drops by 0.4 to 0.5 percent. A typical rooftop PV array may measure 55 to 75°C (131

to 167°F), which means its electrical output would fall by 12 to 25 per cent below the name

plate rating. For example, a 10-kW array only generates 7.5 to 8.8 kW under these

temperature conditions. A PV/T system lowers the photovoltaic temperature by 10 to 20°C

(18 to 36°F), which increases the electrical output by five to 10 per cent, or an extra 0.5 to 1

kW for a 10-kW array.

The performance of the SolarWall PV/T hybrid technology was established through testing at

the National Solar Test Facility, in conjunction with the International Energy Agency Task

35.  The results documented that adding the SolarWall thermal component to a PV array

boosts the total solar efficiency to over 50%, compared with 10 to 15% efficiency for most

PV modules alone. The heat from the PV panels, captured by the SolarWall perforated

absorber, was documented to be three times more than the electrical energy generated

from the PV modules. This means that by being able to uniformly capture and utilize the

excess heat, it becomes possible to realize an energy output improvement in the range of

200-300%, depending on air flow and other design considerations.  The test data also

showed that the temperature gain from the PV modules is between 6°C to 20°C or well

within the typical range for a conventional single-stage SolarWall solar heating system.

How SolarWall® PV/T Systems Work:

The SolarWall® PV/T technology is a building integrated

solution that solves the overheating problems found in most

building integrated PV (BIPV) systems by removing the heat

from the back of the PV modules.

PV modules are mounted on top of the SolarWall® panels,

which act as the PV racking system. The heat is drawn off the

back of the PV modules and is ducted into the building's

conventional HVAC system where it offsets the heating load.

PV - with SolarWall behind - ensures uniform air cooling around each PV module.

 

The SolarWall system keeps the air circulating evenly around

the PV modules, which can cool the PV modules by as much as

20 degrees C. This can increase the electrical output by 10%. 

  

The hybrid system delivers both heat energy and electricity in usable form.

In warmer weather,

dampers are used to

direct the heat away

from the building if the

energy is not required.

Strategic placement of

PV modules is important

to maximize the cooling

benefit. When PV

modules get placed in an unbroken line up the slope of a roof,

it is difficult to dissipate the heat between the panels and the

top part of an array will normally overheat. With the addition

of the SolarWall component, small gaps are left between each

PV module, further helping to prevent excessive heat build-up.

The technology works with any conventional PV module

and can be custom engineered based on site conditions.  The

electrical and heating outputs of the system are sized based

on the energy requirements of the building.  The hybrid

technology is also available in a modular rooftop version

called SolarDuct PV/T.

 

Consider This: On a

sunny day, 100

watts/ft2 of solar

radiation shines down

on a solar PV array. 

10-15

watts/ft2 converted into electricity by the PV panels

10 watts/ft2 lost due to reflection off the PV glass

75-80 watts/ft2 converted into heat energy.  With a

conventional PV array, this sizable form of energy is not

utilized for heating purposes, and in fact decreases the

electrical output of the PV if it is not dissipated.

 The SolarWall® / SolarDuct® system recovers half or

35-50 watts/ft2 of thermal energy for heating buildings

SolarWall® Solar Drying Adds to both Yield &  Bottom Line 

9,000ft2 SolarWall® system is used to dry coffee beans at this plantation in Panama.

The SolarWall technology is used for a variety of agricultural process applications.  In

addition to its substantial usage for poultry and livestock ventilation it is also ideally suited

for other agricultural applications, such as crop and process drying.

Many of the world’s most important crops need to be dried to remove moisture as part of

the production process. Removing the moisture from crops such a coffee beans, tea leaves,

cocoa, nuts, fruit, rice, spices, corn, etc. is an essential process that helps transform the raw

goods into the final product. It is also extremely resource intensive when using mechanical

drying methods that rely on wood, propane or oil.  In more traditional drying operations, it is

common for produce to be passively air-dried in the sun, which takes significantly longer

than mechanical drying and can lead to a higher rate of spoilage and uneven moisture

levels.

 

Agricultural and agri-food operators consume tremendous quantities of energy which

represent a sizable proportion of their total input costs. Rising energy prices has been

putting downward pressure on agricultural incomes in countries around the world, which is

why solar energy represents a tremendous opportunity for the agricultural sector.

For these reasons, upgrading the drying operations to include solar yields a double-benefit

in terms of: (1) Energy savings, and (2) Producing the best possible finished food-product.

SolarWall® systems have been used for drying coffee, tea, spices, cocoa, herbs, fruits, nuts,

rubber, rice, manure, lumber and many other products in countries around the world. It can

either act as a stand along system, or as a preheat to traditional mechanical operations, and

can be easily incorporated into tunnel, trough or conveyor dryers.

As well, many food products require low temperature heat (i.e. up to 50 C or 120 F) which

SolarWall systems are ideally suited to deliver.  This preserves the quality of the produce,

which produces a higher yield.  As well, the SolarWall technology removes humidity from

the incoming air because it is heated before entering the building or drying chamber, which

means that the air has been preconditioned to absorb more moisture.

Proper drying is also associated with a decreased incidence of mycotoxins, especially on

corn (maize) and other crops.  Adequate drying of crops is essential to help minimize the

risk of mould growth and mycotoxins after the harvesting of crops, and solar drying is

considered to be an effective preventative measure against mycotoxins.

 

Workers at the Malabar solar tea drying facility in Indonesia.

SolarWall systems are also highly effective and cost-efficient in other process drying and

heating applications. Dryers need low grade heat sources to heat large volumes of air. Many

commercial dryers run on fuels that burn hot; in many cases, more heat is produced than is

actually needed and goes to waste. Not so with SolarWall systems. From commercial drying

of laundry, to drying woods and manure, to curing leathers, and from heating swimming

pools to preheating combustion air for furnaces, SolarWall drying systems work without fuel

waste, and sometimes without any fuel use at all!

For products or processes that require higher temperature heat, SolarWall systems can still

act in a pre-heating capacity and displace a percentage of the total heating costs.

Many traditional drying systems use wood for fuel, which exacerbates deforestation.

Harnessing the power of solar energy for heating purposes reduces the quantity of trees

that are harvested for fuel, which is very beneficial to curbing deforestation.

 

The heat from the SolarWall system is used to dry fire hoses in this LEED Gold Fire Hall in

Richmond, BC.

Each square meter of SolarWall panelling produce the same amount of heat generated by a

500 watt heater. By installing a SolarWall system, burners not only get turned down, they

often get turned off completely for extended periods of time.

Every client can tell such a story – and every client is enjoying substantial energy savings.

For instance, the Sonoma Herb Exchangein California saves 31 million BTUs annually by

displacing 325 gallons of propane that would be needed if fossil fuels were used instead of

solar power. Keyawa Orchards, which dries over 12 million lbs. of walnuts every year, enjoys

fuel savings of 1,431 million BTUs a year, with corresponding annual cost savings of

$13,800. Coopeldos R.L.; a coffee installation in Costa Rica is enjoying annual savings of

25%. And on it goes. Click here for more examples.

As a result, the same technology that lets the SolarWall technology lead the way in using

solar energy to heat buildings is now setting solar crop drying and solar process heating

standards worldwide for both agricultural and commercial applications.