STYLEPARK ISH
Smart Strategies

Alexander Russ: One topic of this year’s ISH are solutions that help achieve climate protection targets and enable an efficient use of resources. What meaningful smart building solutions are available in the fields of water and energy as regards existing buildings?

Matthias Rammig: Smart planning is the most important thing at the start of a building project. In other words, you consider carefully which measures will have the greatest effect in terms of saving energy and improving comfort. This means identifying the weak points in a building and developing efficient solutions to reduce the carbon footprint as far as possible.

Felix Thumm: The term “smart building” is often understood to mean that the entire building can be controlled via a smartphone. However, as we see it smart building essentially means that a building automatically detects when people are in it and then for example regulates the temperature of the rooms or the lighting. Another example would be that the building recognizes that when the sun shading is lowered there is not enough light in the room and makes the necessary adjustments. However, this is very complex in terms of the technological inputs so it makes more sense to think about which solutions are actually meaningful. It is important to plan robust buildings that are not too complicated and are easy to maintain.

One topic that is much discussed in the media right now are heat pump. In one of your projects, where you modernized a 1970s high-rise residential building in Pforzheim one of the measures was to install a heat pump. Can you explain the energy concept behind that?

Matthias Rammig: First of all, we upgraded the building envelope to achieve an excellent thermal level, namely passive house standard. In addition, a capillary solar absorber was integrated into the facade that extracts heat from the air thereby providing heating and hot water. The energy obtained is harnessed by means of heat pumps or fed into a large water tank, namely an ‘ice storage facility’, where it is stored. If the energy drawn from the facade is not sufficient then additional energy is drawn down from the ice storage tank. The reason for this specific solution is that a geothermal plant was not possible on site there.

Generally speaking, how suitable are heat pumps for existing buildings?

Matthias Rammig: There are often several problems in existing buildings: Typically, the energy performance of the building’s shell is very poor. Added to which, inside the radiators tend to be small in size and therefore have to deliver a considerable amount of heat for the room in order to compensate for the loss of heat through the facade. This means setting high flow temperatures something that used to be achieved using fossil fuels like coal, oil, or gas. However, using fossil fuels is no longer an option because we can no longer afford to go on blowing emissions into the air if we are to protect our climate. As a result, we have to ensure heat pumps are run as efficiently as possible. This can be accomplished by doing two things: First, by lowering the heating temperature, something that can be achieved by insulating the building’s envelope, and second by increasing the heat surfaces so as to adequately heat the room sufficiently but at a lower temperature. In addition, it is important to use sources of energy for the heat pump that are as efficient as possible.

What sources of energy would come into question?

Matthias Rammig: Right now, the marketing agents are plugging air source heat pumps most for the detached house sector because they are very simple to operate and not that expensive. However, there is one decisive drawback to using them: Precisely in winter when you need the greatest amount of heat the air source pump delivers the least energy and this has to be offset by resorting to electricity. That’s why it’s important to combine the whole thing with renewable sources of energy or a storage option like we did in Pforzheim in the form of the large water tank as ice storage. Other options are geothermal probes, groundwater wells or waste heat recovery from wastewater pipelines and flowing water using heat exchangers. It also makes sense to generate the electricity needed to operate the heat pump yourself. That’s why in Pforzheim we installed solar panels and a small wind turbine on the roof.

Felix Thumm: The heat pump is being touted now as the smart system for the building sector and there’s no doubt it has a role to play but it is definitely not the silver-bullet solution because the problem of the heating sector – namely the high energy consumption in winter – is then merely shifted to the electricity sector. But to get back to the topic of smart building: moving forward heat pumps will require an intelligent control system if say they are to meet hot water requirements correctly. In other words, you need a thermal store which can be loaded at night. That means it would be possible to reduce the strain on the electricity network somewhat at certain times of the day. This would require IT solutions to network the heating and electricity sector.

At this precise moment there is great uncertainty about our energy supplies. What form might future-proof systems for existing buildings take and what role would smart building play?

Matthias Rammig: For detached houses a heat pump combined with geothermal energy is without a doubt a sensible and efficient system. However, in the urban context heating networks will fulfill an important function. It is a matter of networking buildings smartly and generating synergies for example by integrating the waste heat from data centers into heating systems. This heat can then be directly inputted into a building or can provide the heating for an entire quarter as part of a local heating network. You can get waste heat at a temperature of 45°C from a data center and that is definitely enough for a building. You can also combine the whole thing well with a heat pump. The latter then has to generate less of a step-up in temperature which in turn leads to higher energy efficiency.

Felix Thumm: However, there are also smart solutions for ventilating existing buildings. One example are window contacts. They contain an integrated sensor that is capable of recognizing automatically whether a window is open or closed. When the window is open the radiator is automatically deactivated. While these may be very simple systems, they nonetheless can have quite an impact. Such systems really make sense in public buildings like schools where there are often no set regulations about who is in charge of closing the windows.

I would like to return to the topic of heating networks for the urban context. One of your projects is a concept for the urban development of the Neuperlach district in Munich. You have designed the concept not only to address new energy concepts but also topics like e-mobility. Can you tell us more about it?

Matthias Rammig: The main issue in Neuperlach was understanding the status quo on the ground. Often planners are not really aware of how high the energy consumption is. With this in mind, we compiled a study that aims to understand Neuperlach as a whole with regard to energy and to see where the greatest emissions are produced. E-mobility plays an ever-greater role in our planning if only because it means additional amounts of electricity are required in a building. On the one hand this results in higher consumption but on a positive note it also means a photovoltaic system can be used more efficiently. As things now stand most electricity in a building is required in the mornings and evenings. But you get most power from solar panels around midday because the electricity generated is normally fed into the network rather than being used in situ. Now e-mobility makes it possible to feed the electricity generated into a vehicle. In this context a smart feature might be that – if needed – the vehicle is capable of returning the energy stored in it to the building. You could say the vehicle would function as a battery.

Felix Thumm: That said the legislation for implementing such concepts is lagging behind somewhat. What’s more, the automotive industry, viewed internationally, is also not everywhere as far advanced in these loading and unloading strategies.

I would like to touch on the subject of water. Another theme at this year’s ISH is the "Sustainable Bathroom". What planning options are there for existing buildings and what role can smart building play?

Matthias Rammig: Well, for example this can be all about saving drinking water perhaps by integrating rainwater or gray water use into the system. The way our water systems are structured at present all our wastewater not to mention the rainwater flows directly into the sewage system. Instead of doing that you could maybe use it for flushing toilets and in that way save drinking water. But typically, such options are not used because of the prohibitive costs they entail.

Felix Thumm: There are very strict laws as well as hygiene standards in this regard. As a consequence, you have to integrate two systems because the guidelines insist you separate drinking water from rainwater or gray water. I would sometimes like to see more pragmatic solutions.

Another topic is touchless systems for faucets to save water and ensure a certain hygiene. How useful an idea do you find that?

Felix Thumm: In principle that makes sense to me. There is relatively little effort involved in installing such devices – one reason being that they work independently and need not be incorporated into an entire automated building system. Naturally, you always need to consider the context. Especially in a public building something like that can be useful because the devices are automatic. They work in a similar way to the window sensors we mentioned previously, i.e., the technology automatically recognizes whether it needs to be in operation or not.

The guiding principle for this year’s ISH is “solutions for a sustainable future”. What would you like to see from industry in this regard?

Matthias Rammig: As planners we would basically like to see simple solutions. And such solutions should also have a certain robustness and be capable at the end of their lifetime of becoming part of the circular economy. Another thing is that often the cycles of technical components are out of sync with the cycles of buildings. So, it’s important to work at rectifying that.

Felix Thumm: Another thing I would wish for is some kind of constant feedback on how much water or energy is currently being used in a residence. With regard to water, it could for example be the faucet system that computes weekly consumption in relation to average consumption levels. There are now projects for apartment buildings where your personal energy consumption is monitored and assessed. This is a great way of potentially creating a greater awareness among users and would also be a smart approach which is not very complicated but at the same time is easy to implement.

ISH 2023
World’s leading trade fair for HVAC + Water
13 to 17 March 2023

Ludwig-Erhard-Anlage 1
60327 Frankfurt am Main