This Roof Does Everything (TFN)
This Roof Does Everything, well not everything but it’s really cool.
What the Trisol Panel might look like. Sharp eyed readers may note that there is an extra layer of glass on this panel
Theoretical Future News (TFN) is a work of fiction and is not a guarantee of our future.
Renewable Energy Today
Aug 7th, 2025
“As a society we aren’t really wired to appreciate how much energy there really is in the world.” I don’t remember exactly what the first thing Trisol Canopies CEO Cara Flores said to me was, most likely something mildly pleasant, but her comment about our use of energy has stuck with me. Of all the teams at this year’s Sustainable Innovations New England finalist’s presentation, Cara’s small team made some of the largest waves.
Trisol Canopies is the culmination of Cara and her team’s University of Colorado Masters Thesis project. The Trisol team (named after the aliens Liu Cixin’s Three Body Problem) was looking to see just how much they might be able to impact home energy consumption.
“We see the Trisol Canopy and associated technologies as the start of the next wave of innovation in rooftop solar. Originally our goal was to analyze how much of a performance boost you could get out of a PV panel if you were to combine air cooling and PDRCs.”
For those less familiar with PDRCs the acronym stands for Passive Daytime Radiative Cooling. PDRCs work in part by emitting a particular frequency of thermal radiation. Our atmosphere is almost entirely transparent to these special wavelengths and so the PDRC can stay cooler than otherwise possible. Readers may have heard how many new LEED Platinum certified buildings are using PDRCs to reduce how much air conditioning they need.
What took you from efficiency research to your new product?
“Late one-night a few summers ago we were packing up our test kit and we felt how cold the rig got once the sun had set. Now, we knew that it was supposed to get cold, that physics is pretty basic. [authors note: maybe for some of us] What was different that night was that my poor air conditioner had met its match with the days heat. I started to think about how much energy we need to heat and cool ourselves. It turns out I started to mumble to myself, thankfully my co-founder Xiang is used to my mumbling and started to ask me some great questions. We started to realize that there was an opportunity to take advantage of so much more of the energy from our experiment than just heat and electricity. We could make electricity, heat, and cold. All of that in a single package.”
What followed was described as a blur of thesis work and late night prototyping. Out of this blur of energy came the Trisol Canopy. From a distance the Canopy looks like so many solar canopies on the market today, black PV panels on a frame designed to allow for something to be placed underneath. The differences begin to emerge as you get closer, this canopy is thicker than most. It’s in that extra volume that the Trisol team has integrated heat exchangers designed to move heat energy to where it’s needed. On the top of the panels is the subtle texture of the PDRCs. ….
Welcome back to the present
It turns out this is a topic I tend to geek out to a rather large degree. It doesn’t help brevity as I’ve had the seed of this concept in the back of my mind for a while, but I didn’t actually start crunching the numbers until writing.
Executive Summary Traditional photovoltaics can convert 15-20% of the sun’s energy into electricity. So called PV-Ts are able to convert more than 70% of the sun’s energy by producing both electricity and heat. Adding Passive Daytime Radiative Cooling materials to the mix could potentially aid in home efficiency by helping make ice at night and reduce daytime cooling needs. What is still unanswered is whether such a proposed system would make financial sense.
To my current understanding of physics the concept of the Trisol Canapy is physically possible, whether or not it makes financial sense is another story entirely. Solar energy that is absorbed by the Trisol Canopy would get converted into electricity and heat. The heat generated by sunlight would then absorbed by the heat capture system, dispersed by the PDRC, or warm the air around the panels. When the panels start to lose more heat from the PDRC than the panel gains from sunlight, it would be at that time the Trisol’s panels could be used to help with air conditioning. The engineering/business question for the Trisol Canopy is roughly. Does my building get more benefit from having a complicated panel that is trying to do three things, instead of having separate elements trying to do a mix of the individual goals, electricity production, heat generation, and helping with cooling?
Generating electricity and heat using the same panels is already an avenue of research. These hybrid panels are called PV-Ts (photovoltaic Thermal). Broadly speaking PV-Ts are a solar cell attached to some kind of heat pump. Traditional photovoltaic panels are only capturing the energy from a narrow band the suns energy, namely UV and visible light. Generally speaking a photovoltaic panel, in early 2020, will be able to convert between 15-20% of the Sun’s energy into electricity. Much of the remaining energy that hits a PV panel is converted into heat energy. For most solar installations that heat energy just kind of does its thing. What PV-T systems try to do is capture some of the heat generated by sunlight hitting solar panel and put that heat energy to use. Some PV-T companies claim that their technology can convert more than 70% of the energy that hits the panel into some useful form. One of the reasons PV-T panels are so cool is that traditional photovoltaic panels lose efficiency as they get hotter, by moving surplus heat away from the photovoltaic cells the cells are able to maintain their efficiency.
You might be asking yourself, if PV-T panels are so good at capturing energy and they potentially make more electricity why don’t more people install them? It all boils down to cost, in a paper written for the International Solar Energy Society the authors investigate what price points an installed PV-T system would make financial sense for property owners to choose PV-T over simply installing separate solar PV and solar thermal systems. In 2016 a Solar Thermal Panel could be installed for as little as $200 per square meter, in the same year a photovoltaic system could be installed on a roof for around $400 per square meter. That would mean, assuming that your hybrid system was producing the same amount of useful energy in the form of heat and electricity, would need to cost close to $600 per square meter installed*.
Where things get super complicated is the question of integrating PDRCs. As PDRCs are a new technology it is hard to find newb friendly equations for accurately estimating performance. The majority of PDRCs are intended to operate 24/7 moving heat into the cold of space. If your goal is to simply produce as much cooling as possible that’s pretty awesome. For a PV-T system adding PDRCs is a weird balancing act, the better the PDRC is at cooling the less power your cooling system will need but your system won’t produce as much heat. For example, let’s say my PDRC can help move 100 Watts per square meter of heat energy away from our panels at the same time our thermal system could normally produce up to 700 watts of heat energy to warm something. That means that our heating system is losing more than 14% of its performance, I know its at least 14% because our peak output is going from 700 watts to 600 watts. The reason it is likely to be more than a 14% performance loss is that during the parts of the day where the sun is still shining, but not providing as much heat energy, there will be times that the radiative cooling will exceed the thermal gain. (exact numbers would require modeling beyond my current skill set)
On the flip side if the PDRCs doesn’t provide as much cooling capacity, we are losing out on a lot of cooling potential. American homes can require a pretty decent amount of cooling capacity to help stay comfortable. Roughly speaking many houses will have air conditioning systems rated at 3-4 tons. Where a ton of cooling represents the ability to produce 1 ton of ice per day, in terms of wattage each ton of cooling capacity represents moving 3.5 kilowatts of heat away from a home. For a house that has a rooftop area of 1200 square feet (112 square meters) and the ability to provide 100 watt/square meter of cooling, your roof should produce roughly 1.6 tons of effective cooling daily.** For many American homes reducing cooling needs by 1.6 tons would equate to reducing their peak air conditioning load by 30-50%.
What does this all mean for Cara and her team?
Their product doesn’t necessarily have to produce more heat energy than a solar thermal panel, it doesn’t need to produce more electricity than a stand alone PV panel, and it doesn’t need to reduce your cooling energy needs by as much as a standalone PDRC installation. What Trisol must do is produce those various forms of energy (I’m including making cold as energy production) in a cost competitive way.
Deciding if Trisol is cost competitive is beyond the scope of this post but I can at least put down a few of the variables and what they would need to have answers for to get a strong customer base
System Installation Cost vs a given mix of PV, Thermal, and PDRC
Maintenance Cost vs a given mix of PV, Thermal, and PDRC
Expected Lifetime of system vs life time of a given mix of PV, Solar Thermal heating, and PDRC
Kilowatt hours of electricity produced per day/month/year
Number of liters of 50+ degree C water produced per day/month/year
Number of Kilowatt hours of energy saved by reduced air conditioner load per day/month/year
How much electricity does Trisol produce vs a PV-T installation vs a PV array with PDRCs added in?
Are there any additional benefits to the building beyond the electricity, cooling, and/or heating? Ex. the panels might act as additional insulation.
What is the difference in the total amount of hot water produced by Trisol vs a more traditional Solar Thermal Installation vs a PV-T installation?
What is the difference in energy savings in cooling while using Trisol vs PDRC panels vs just benefiting from surplus heat from solar panels going into making hot water?
Are there any policies that incentivize a combined functionality approach for Trisol that provides financial incentives for consumers?
That’s a daunting number of variables, but we should remember that you don’t need answers to all of them. Very frequently products are only better than their competitors in a small sub set of ways, and more frustrating for engineer types, those “improvements” might not even be functional, but simply marketing/aesthetics.
A Cutaway view of one potential design for the Trisol
1: Transparent Cover: Helps keep heat in (must be transparent to PDRC emission frequencies)
2: Insulating Gas Layer: Another way to limit non-useful heat loss. Using Carbon Dioxide should allow the IR emission band of the PDRC through
3: PDRC: This design presumes it is necessary to place the PDRC on top of the PV layer, it may not necessarily end up like this
4: Photovoltaic layer
5: Radiator Fins
Here are some ways the Trisol team might be able to make sure their product makes the most sense for consumers.
System cost: A big reason why PV-Ts are expensive to install is routing the plumbing for the heat exchanger for the system, in theory designing the panels to move heat around by moving air instead of pumping a liquid could reduce installation costs. Another impactor on installation costs is the level of skill required for the installation, if the Trisol system is designed in an easy to install modular fashion that could keep labor costs down. If 1st gen Trisol Canopies are designed from the get go to be a single good enough unit that arrives mostly assembled in a plug and play fashion that ease of rapid deployment might be enough to offset costs/performance risks.
An alternative way to approach the economics of Trisol would be a modular design that would allow for a mix and match of panel types depending on needs of the building owner and the climate. If you are somewhere consistently on the cooler side, you might only install traditional PV-T panels, hotter equatorial climates might include a large percentage of panels that are just PDRCs without and PV elements.
Thermal performance: While current PDRCs are generally focused on always trying to lose heat, there is some research into PDRCs that try to reduce heat loss if it is no longer warm enough outside to need cooling. It wouldn’t be too crazy to imagine that researchers might make a PDRC that only selectively loses heat as needed. If the PDRC can be turned off or on as needed and done in a cost effective fashion that would improve how much heat the system might be able to generate. Depending on how much control the system could have over the PDRCs, you could imagine a building adjusting its performance throughout the day. Is the hot water tank full? Let the PDRCs operate at maximum cooling.
Synergies: Many designs for PDRCs and solar thermal systems are built around the idea that the panels are relatively insulative. Solar thermal systems want to capture as much heat as possible. PDRCs want to help cool what they are attached to, not the air around them. This means the panel modules should be relatively insulative and help to reduce a building’s heat loss. (honestly this is more likely something marketing would overhype instead of a major benefit for consumers, as a well installed roof should be insulated to begin with)
Financial incentives: Taxes can provide interesting motivations for designs. One of the reasons traditional homes in Amsterdam are so narrow is that the old tax laws in the city taxed homeowners on the footprint of the house, not how many square feet you had (or property value). Rooftop energy could experience government tax incentives if a country has aggressive climate goals, they might want to incentivize homeowners to capture as much energy as possible, which would motivate installing PV-Ts. Other laws might modify the taxes on citizens/businesses by increasing the cost of electricity produced by the grid and provide breaks for reducing energy demand in particular categories of electricity use.
Selling the excess: In many places homeowners are able to sell their electricity back to the power grid, what would it look like if someone with a Trisol system could sell their excess hot and cold? This would certainly require some changes in how cities get built, but it isn’t without precedent. In big cities like New York, many buildings don’t actually have their own furnaces, instead they get their heat from steam pipes. Technologies like the Trisol Canopy with the right kind of infrastructure could do the same thing. Rooftops throughout a community could produce their own, heat, cold, and electricity. When a given building has met its own needs for what it can reasonably store, the surplus could go through pipes to where the the hot or cold water would be of use.
Okay this is already way too long, so I’m going to wrap up here. I think there are many ways for a technology like Trisol to make our world more efficient. While I honestly can’t say with certainty whether integrating PDRCs into a PV-T system would actually make any deep financial sense, I think the concept warrants a more in-depth analysis with more sophisticated tools. Personally I think the first generation of the Trisol system would be something that would come as 3 or 4 big parts sent in a shipping container, the final package would look like the render that was the visual for this article.
I hope this was interesting, please feel free to ask any clarification, this article ended up being more narrow in potential in audience than I intended on the offset so if you are lost on something that is more likely a failing on explanation than your reading ability.
*There is a potential exception for businesses that want as much energy from their rooftop as possible. These ideal customers might put a premium beyond the $600 per square meter that other customers might want. Other groups might prefer limiting how much of their roof that needs to be modified
** Under optimal conditions, assuming that the PDRCs are providing 100 watts of actually cooling a working fluid for 12 hours. Roof cooling rate = 11,200 watts Run time = 12 hours Roof Cooling value = roof cooling rate*run time = 134,400 watt hours =134.4 kWhrs: 1 ton cooling =3.5kilo watts *24 hours = 84 kWhrs
Roof Cooling value tons = 134.4. kWhrs/84kWhrs/ton =1.6 tons