When can we talk about sustainable construction?

Precisely calculated selection of solutions and heat sources, embedded in an environment that respects biodiversity and generates as few costs as possible during construction and operation - these three principles of sustainable construction only translate into what we call ‘green building’ in practical solutions.

Real estate is one of the priority sectors to help meet ambitious climate targets - as it accounts for 38 per cent of global CO2 emissions. Energy savings also mean real financial savings, which is why investors are also looking closely at sustainability solutions.

According to an expert approach, sustainable buildings are characterised by minimal consumption of natural resources during construction and operation and low negative impact on the environment and biodiversity, while maintaining optimum usability for the owners.

Sustainable construction is more than ‘green solutions’

- Truly sustainable construction must be distinguished from construction with green solutions. The former is based on a holistic approach - in terms of both the choice of solutions and the layout of the building, its location in harmony with the environment and the needs of the inhabitants. The location of the building is chosen, ecological materials are used, every choice is justified and calculated. In such a case, we always start with meticulous calculations and it is these that decide on the details, which only translate into the choice of solutions ,’ explains Marcin Kosieniak, a specialist in engineering solutions and co-owner of PM Projekt design office.
How to reconcile these elements in practice so that, in addition, the price of the investment is also optimal?

Marcin Kosieniak explains the use of individual elements using a concrete example.
- Nowadays, we carry out a lot of such eco-constructions and, of course, those realised in the city are different from those realised, for example, in the Mazury region, also due to the climatic conditions. In the case of realisations in the Masuria region, of course, the role of blending in with the surroundings is a task for each partner in the process, starting with the investor, through the architect, HVAC specialists and the developer,' he enumerates.

How do you navigate through the possibilities and what should guide you in the reasoned choice of solutions?
What does the selection of individual solutions look like in practice? Quite common is the choice of heat pumps used to produce the heating medium for heating the building and for domestic hot water. It is often a matter of detail.

- For example, in one of the projects we are implementing in the Masuria region, we used ground-source pumps instead of air-source pumps because ground-source pumps have a higher COP and this means much greater energy efficiency. Using heat pumps for hot water preparation results in lower costs during warm periods, i.e. when consumption is highest. In addition, in order to ensure the highest possible energy efficiency factor, the entire facility has underfloor heating,’ Kosieniak points out.
The biggest energy consumption is for this type of development (such as the Yacht Apartment in the municipality of Harsz) for the year-round swimming pool.
- The air temperature in the pool has to be sufficiently high, and we also have to heat the water in the pool basin, which is a constant consumption of energy and heat. Here, we used a very energy-efficient solution. Of course, we used heat pumps for heating and hot water, which are responsible for maintaining the temperature in the room. Heat pumps are also used to maintain the temperature of the pool water. In addition, we used heat recovery from the air exhausted from the pool and an additional heat pump system for the pool ventilation itself,’ explains Kosieniak.

Climate zone also matters

The facility was equipped with the maximum number of photovoltaic cells, and their number was decided by precise calculations.

- Thanks to the calculations we made, we were able to ensure that the photovoltaic cells would not overproduce and that it would be possible to use it in the facility for current energy consumption,’ argues the co-owner of PM Projekt.

Interestingly, it is not only the parameters of the building that are important, but also the surroundings, including which climate zone the investment is located in. The municipality of Harsz is located in climate zone IV of the country, which means that the calculated outdoor temperature is -22*C. What significance does this have?

- In Gdańsk, for example, there is climate zone I, where we calculate an external temperature of only -16*C. And this is a 6K difference, so a lot more heat is needed by the same object in Giżycko than by an identical object in Gdańsk,’ explains Kosieniak.

As he adds, thanks to the solutions applied in the case of the Yacht Apartment in the Mazurian Lake District, not only has the coefficient of primary energy use been met in accordance with national requirements (EP), but it is much lower than required for this type of building.

What do the greenest buildings have?

Kosieniak also points out that the most opportunities are offered by the realisation of high-rise bourgeois-service-residential buildings in the premium market.

So what solutions can be designed within HVAC solutions, with precise energy analyses?
- If I were to use an example of the most advanced solutions we design, I would start with something illustrative - like the fact that we use variable airflow controllers to adjust the amount of supply and extract air from rooms based on CO2 pollution sensors or other room presence sensors. This ensures that the ventilation systems operate when people are in the rooms, which is exactly when ventilation is needed there. So there are no schedules set rigidly. Importantly for the overall project, we design and use systems that recover condensation heat, i.e. while producing cooling for the building, they simultaneously transfer the heat to other consumers.

These other consumers are, for example, domestic hot water systems or systems for reheating air in dehumidification processes. We recover heat from the exhaust air in the air handling units,’ Kosieniak enumerates.

Enumerating further solutions in this type of modern eco building, Marcin Kosieniak points out:
We direct the exhaust air from clean rooms such as offices, conference rooms, lobbies, etc. into the garage instead of outside. - In one such project involving us, we heated the garage in this way without any heating equipment (!) ,’ he adds.

Heat pumps that work in the transitional period and in the cold period switch off in favour of heat from the hub.
Rainwater is recovered and then directed to flush the toilets.

- The premium high-rise we are currently working on is additionally equipped with photovoltaic cells and control algorithms set to minimise energy consumption. Of the building solutions, we use facades with the lowest possible heat transfer coefficients. In addition, we use a solar absorption coefficient of 0.30 for the glazing in summer, which is really a very low value on the market. The well-planned placement of plants is not without significance. Wellbeing is also one of the elements playing an important role in eco-design today ,’ adds Marcin Kosieniak, co-owner of the design office PM Projekt.

The number of certified buildings is increasing year by year. According to a recent report by the Polish Green Building Council, less than 40 million square metres of space are already certified in Poland.
On the Polish real estate market, there are five green building certification systems: the British BREEAM certificate, the American LEED, the French HQE, the German DGNB or the WELL certificate, which is focused more on man himself, on his well-being in the building. They all focus on environmentally friendly aspects, such as the energy efficiency of the building or water management, and on creating a friendly working environment.

Author: Marcin Kosieniak, PM Projekt