This Modular Wall System Has Built-In Solar Panels, Heat Pumps, and Ventilation
We like to repeat the saying by architect Carl Elefante that “the greenest building is the one that’s already there,” but there are countless millions of square feet of office buildings around the world with leaky curtain walls and inefficient heating systems that need to be modernized over time couple of years. The German research organization Fraunhofer has found a really interesting solution for the typical pillar and prefabricated buildings of the 50s to 70s: a prefabricated wall system with an integrated heat pump, ventilation with heat recovery, highly efficient glazing, with the fixed parts of the wall covered with photovoltaic panels are.
According to the Fraunhofer press release:
“We’re not renovating the entire building, just the facade. In the future, the old facade will be replaced by new, industrially prefabricated modules with integrated system technology and a multifunctional solution based on the latest energy standards will be created, ”explains Jan Kaiser, project manager and scientist at Fraunhofer IEE. “All heating, cooling and ventilation devices required for the adjacent offices are integrated into the facade.”
The technical part of the unit, which contains the heat pumps and ventilation, is 1.2 m wide and 30 m deep as standard, insulated with vacuum panels and can serve an area of around 260 square meters. Installation only takes a few hours, says the press release: “Since the heating and ventilation technology is already integrated, no new pipes have to be laid within the building. The facade only needs a power connection to continue air conditioning and ventilation. “The rooms in times without PV power.”
There is no information about how much electricity the solar panel generates or what percentage of the electricity that is required to operate the heat pumps and the ventilation system is estimated to be covered. We’ve asked and will update if and when Fraunhofer will respond, but I suspect it’s not much. It’s still a very good idea, however, and the whole system is said to reduce power consumption by 75%.
“The new modular facade RE offers perfectly coordinated protection against heat and solar radiation with low power consumption and a high level of user comfort,” emphasizes Michael Eberl, scientist at Fraunhofer IBP and working on the project together with Jan Kaiser. Between 1950 and around 1990, around 25 to 30 percent of all office buildings in Germany were built using the frame construction method. Together they consume 3200 gigawatt hours (GWh) of electricity annually. “Using our RE module facade would reduce this to 600 GWh. The high degree of prefabrication would also increase the low renovation rate of just one percent per year, ”explains Kaiser.
The ventilation system appears independent of the heat pumps and is based on a LTG single-channel impulse ventilation system “breathing”. On the Fraunhofer website it says: “In contrast to conventional facade ventilation devices, FVPpulse does not have separate air ducts for outside and exhaust air, but has a single fan and only one opening in the facade, and a flap system switches cyclically between the intake and exhaust function. This unsteady ventilation results in a good mixing of the room air at low air speeds and large amounts of air. ”
We have already seen pulsed ventilation systems on the tiny Lunos HRVs, which have a heat exchanger core that is heated when the air goes in one direction and returns the heat when it is reversed. It looks like this device works the same way and claims heat recovery efficiency of up to 90%.
In a way, this could be a missed opportunity: Alex De Gagné’s Minotair “Magic Box” integrates the heat recovery fan into the heat pump and performs even better. He was supposed to develop a vertical version, which would probably be a better wall unit for the Fraunhofer concept.
Fraunhofer really has plans here. It’s a quick and easy plug-and-play answer to a serious problem. The American writer Stewart Brand wrote in “How Buildings Learn” that “a building always tears itself apart due to the different rates of change of its components”. The columns and slabs of a concrete office building can last a long time, but the skin has a shorter lifespan and, according to designer and architect Rachel Wagner, “often has the greatest impact on the long-term durability, user comfort and energy efficiency of the building”. . ”
Here, Fraunhofer solves problems with insulation, glazing, heating, cooling and ventilation in one movement, many of the things with the short lifespan that have the greatest impact in this climate crisis. This is clever stuff.