Solar Thermal
Collectors that turn sunlight directly into usable heat — even on overcast and winter days — proven for decades across Europe and Asia.
- Space heating & cooling
- Domestic & process hot water
- New builds and retrofits
Commercial renewable heat & power · St. Louis, MO
Turn heat into your lowest-cost energy.
Rabco Energy Solutions engineers, integrates and installs commercial solar thermal, geothermal and waste-heat-to-power systems — designed to replace a larger share of fossil fuel and pay back in years, not decades.
5–25 MWCommercial geothermal & waste-heat projects
U.S. + EuropeEngineering and installation experience
NationwideNew construction and retrofits, based in St. Louis
What we do
Three ways to put heat to work.
Heating, cooling and hot water make up a large share of a commercial building's energy bill. We focus on the technologies that tackle that load directly — and generate clean power where the resource allows.
Enhanced Geothermal (EGS)
Engineered reservoirs that bring geothermal power to places without natural hot springs or steam — including the Midwest.
- Site screening & feasibility
- Surface plant integration
- Heat & power offtake design
Waste Heat to Power
Capture heat your operation already throws away and convert it into electricity with Organic Rankine Cycle systems — with no capital outlay for qualifying sites.
- Heat recovery assessment
- ORC system integration
- Funded energy-purchase program
Commercial solar thermal
Take hot water, heating and cooling off the utility bill.
For most commercial buildings, the biggest energy loads are thermal — not electrical. Rabco's solar thermal systems turn sunlight directly into heat and plug into the boilers, water heaters and HVAC equipment you already run, so your conventional systems work far less of the time.
300°F+Collector temperatures from evacuated-tube arrays
No rip-outIntegrates with existing HVAC, boilers and storage
3 loadsWater heating, space heating and absorption cooling
Where it pays off
Built for buildings that use a lot of heat.
Solar thermal delivers the fastest payback where hot water or heating demand is steady all year. If your facility is on this list, it's worth a look.
Hotels & hospitality
Guest rooms, laundry and kitchens drive constant hot-water demand.
Healthcare & senior living
24/7 occupancy with high sanitation and domestic hot-water loads.
Multifamily
Central domestic hot water serving dozens or hundreds of units.
Food & beverage
Washdown, cleaning-in-place and process water heating.
Schools & rec centers
Showers, kitchens and pool heating across long operating hours.
Commercial laundries
Some of the highest hot-water volumes per square foot of any business.
How solar thermal works
Sunlight in. Usable heat out.
A closed-loop system that does one job very well: move solar heat into the equipment your building already relies on.
Collect
Evacuated-tube arrays on rooftops, carports or any sunny surface heat fluid to well over 300°F — even on overcast and winter days.
Transfer
A pumped closed loop carries that heat through heat exchangers into insulated storage tanks.
Deliver
Stored heat serves domestic hot water directly, feeds your boiler for space heating, or drives an absorption chiller for cooling.
Control
Sensors and controls tie into your existing system, holding set-point temperatures and running your conventional equipment as backup.
For facility managers
Designed to sit alongside what you already run.
Solar thermal isn't a replacement for your boilers or chillers — it carries the bulk of the load so they don't have to. That keeps the risk low and the operations familiar.
Sizing rule of thumb 80–120 gal/day
of hot water from each evacuated-tube collector, using roughly 50 sq ft of roof space. Commercial systems range from a few collectors to several hundred.
- Your existing equipment becomes the backupSolar is configured as primary; legacy systems cover nights and long cloudy stretches.
- Low maintenanceClosed-loop systems need little attention; a twice-yearly preventive check is typical for commercial installs.
- Modular and fault-tolerantIf a tube is damaged, the rest of the collector keeps working and the tube swaps out at low cost.
- Long equipment lifeAbsorption chillers have a median service life of around 23 years, per ASHRAE, with few moving parts.
- Proven technologySolar collectors and absorption chillers each have decades of track record — and wide adoption across Europe and Asia.
Waste heat to power
Your process already makes the fuel. Use it.
Exhaust stacks, engines, kilns and ovens send valuable heat into the air every hour they run. Rabco captures that heat and converts it into electricity with Organic Rankine Cycle (ORC) systems — and for qualifying sites, we fund the equipment.
$0 capitalFor qualifying facilities under our funded program
Liquid or gasHeat captured from one or multiple sources
Minimal disruptionLittle or no impact on your core process
Quick fit test 5,250+ hrs/yr
As a rule of thumb, waste heat power is an excellent investment at sites running above a 60% capacity factor — roughly 5,250 operating hours a year or more.
Where we find heat
If it gets hot and runs often, it's a candidate.
We recover heat from flue, stack, vent and combustion gases, as well as hot liquids, across a wide range of temperatures.
Engines & turbines
Combustion turbinesReciprocating enginesMicroturbinesCHP / cogen exhaustFuel cells
Heavy industry
CementOre processingPetrochemicalsRefineriesPulp & paperGlassGas compressor stations
Manufacturing
Thermal oxidizersPaint & industrial ovensBrick kilnsAir & gas compressorsLarge boiler stacks
Food & beverage
Fry & chip linesBakeriesBreweriesWineriesBottling
Power & marine
Power plant exhaustSteam condensersWaste steamContainer & cruise ships
How ORC works
Like a steam turbine — tuned for lower temperatures.
The Organic Rankine Cycle works like a conventional steam cycle, but swaps water for an organic working fluid with a much lower boiling point. That lets it make power from heat that's too cool for steam.
Capture
A heat exchanger pulls heat from your exhaust or hot liquid stream without touching the process itself.
Evaporate
That heat boils the organic working fluid into a high-pressure vapor.
Generate
The vapor expands through a turbine or expander, driving a generator to produce electricity.
Condense & repeat
The vapor is cooled back to liquid and pumped around again in a sealed, closed loop.
Engineered to your temperatures. Hotter sources change the choice of working fluid. In some cases we moderate inlet temperatures so lower-cost fluids can be used; for high-temperature sources, we evaluate whether a trans-critical cycle delivers more power.
Why plant managers say yes
New revenue from an existing byproduct.
Use it or sell it
Run the electricity in your own plant, or sell it to the grid for a steady additional revenue stream.
Process stays untouched
Heat recovery sits downstream of your operation with little or no impact on production.
Lower emissions
Every kWh you generate is one you don't buy — cutting purchased power and its emissions.
Fits your footprint
Flexible plant layouts work within the space you have, and can be designed to add heat sources later.
The Power of Waste Heat program
Lower energy costs with zero capital outlay.
Many businesses want to cut their carbon footprint but can't make the numbers work. For qualifying facilities, Rabco funds a custom heat-recovery energy system and sells you the energy it produces at a rate below what you pay your utility today.
At the end of the agreement, you can renew or buy out the equipment — and keep generating your own power for years to come.
- No capital expenseWe pay for the system on qualifying projects.
- Immediate savingsEnergy is priced below your current utility rate from day one.
- Price stabilityYour energy cost won't increase for the life of the agreement — a hedge against rising rates.
- Path to ownershipBuy out the equipment at term end and generate your own energy.
- A visible sustainability winA credible emissions-reduction story for customers, employees and your community.
A partner for the whole lifecycle
From site study to years of service.
Site study
Map heat sources, temperatures, flows and operating hours.
Design
Select the cycle and working fluid; size the plant to your heat and space.
Build & commission
Install, integrate and bring the system online.
Optimize
Tune performance and train your team.
Service
Ongoing support and upgrades as your process changes.
New · Enhanced Geothermal Systems
Geothermal power, no longer limited by geography.
Conventional geothermal needs hot rock, water and natural permeability in the same place — which is why it has been confined to a handful of western states. Enhanced geothermal systems (EGS) engineer the missing pieces, creating a human-made reservoir in hot, dry rock so clean, firm power can be produced in far more locations.
Drill into hot rock
Wells are drilled deep enough to reach rock hot enough for power or direct heat — using directional drilling techniques adapted from oil and gas.
Engineer the reservoir
Fluid is injected under controlled pressure to open a network of small fractures, creating permeability where nature didn't.
Circulate and capture heat
Water travels from the injection well through the hot fractures to a production well, absorbing heat along the way.
Generate firm power
At the surface, a closed-loop binary (Organic Rankine Cycle) plant converts that heat into electricity — the same technology behind our waste-heat systems — then the cooled fluid is re-injected.
Always on
Baseload power 24/7, independent of weather or daylight — no battery storage needed to firm it up.
Works in more places
Extends geothermal beyond traditional hydrothermal regions toward nationwide deployment.
Small footprint
Compact surface plants use far less land per megawatt than most generation sources.
Proven supply chain
Builds on decades of drilling, completion and reservoir know-how from the oil and gas industry.
90%Cost reduction targeted by the DOE Enhanced Geothermal Shot™
$45/MWhDOE's 2035 cost target for EGS electricity
65M+U.S. homes and businesses EGS could power, per DOE
~3.7 GWTotal U.S. geothermal generation today — a fraction of the resource
Where Rabco fits
We help commercial, industrial and community clients evaluate whether EGS heat or power makes sense for their site, and integrate the surface side — binary/ORC power plants, heat exchange and direct-use systems — drawing on our geothermal and waste-heat engineering experience.
Sources: U.S. Department of Energy, Geothermal Technologies Office — Enhanced Geothermal Systems and Enhanced Geothermal Shot™.
Questions we hear
Frequently asked questions
Solar thermal
Can solar thermal replace our current water heaters or boilers?
It can carry the bulk of the load, but we design it to work with your existing system or with a storage tank that has gas or electric backup. That way you're covered during extended cloudy periods and at night.
Does it work in winter or on cloudy days?
Yes. Evacuated-tube collectors are built for cold and overcast conditions. During long stretches of cloud cover, your backup system may run more often to meet demand.
Flat-plate or evacuated-tube collectors?
Flat-plate collectors suit warm, sunny climates and tight budgets. Evacuated tubes cost more but perform better in cold or cloudy conditions, so we generally recommend them for space heating and Midwest installations.
Can solar thermal cool a building?
Yes. Solar heat can drive an absorption chiller that runs alongside your existing air conditioning, so the conventional system operates a much smaller share of the time. These systems need flat roof space and room for chillers and cooling towers, so they're best suited to commercial buildings.
How much roof space do we need?
Plan on about 50 square feet per evacuated-tube collector. We'll size the array to your hot-water and heating loads during the assessment.
Waste heat to power
How do I know if my facility qualifies?
The strongest candidates run most of the year (above roughly 5,250 hours) and have a consistent source of hot exhaust or liquid. Fill out our assessment checklist and we'll give you a straight answer.
Will this affect our production process?
Heat recovery is designed to have little or no impact on your main process. It captures heat that would otherwise be released, downstream of where you use it.
Can we recover heat from more than one source?
Yes. Our systems can collect heat from multiple sources, whether liquid, gaseous or a combination of both.
What happens at the end of the funded agreement?
You can renew the agreement or buy out the equipment and continue generating your own electricity.
“Cities and businesses face countless choices about how to generate and use energy. Those choices call for unconventional thinking — the kind that leads to lasting answers.” Tab S. Cohen, President, Rabco Energy Solutions, Inc.
About Rabco
Engineers and installers who've done this before.
Rabco Energy Solutions is a St. Louis-based engineering, systems integration and installation company. Our engineers, technicians and certified installers have delivered solar thermal and geothermal systems in the United States and Europe, where these technologies are already mainstream.
We serve new construction and retrofits nationwide, and develop commercial geothermal and waste-heat projects at a 5–25 MW scale. The best way to get to know us is to tell us about your building, facility or community's energy needs.
Start a conversation
Let's see what your site can save.
Tell us a little about your project and we'll come back with initial ideas for a system that fits.
Email
[email protected]
Phone
636-536-0386
Based in
St. Louis, Missouri · serving clients nationwide
Helpful to include
Solar thermal: a year of utility bills and some basics about your building — we'll return a preliminary system concept.
Waste heat: your heat sources and operating hours, or the completed assessment checklist.