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For the water supply of the community Ipsach in Switzerland, the question arose as to how heat could be provided for the supply plant in a sustainable way. The engineering firm EPRO was asked to do this. The result is convincing!

Pictures: ©EPRO Engineering

The waste heat generated in the Swiss community Ipsach is put to good use for the water supply plant. This was made possible by EPRO ENGINEERING on the basis of a transparent decision-making process. Using simulated energy flows for demand and generation, the engineering company shows the technical possibilities transparently and proposes ecological solutions that can be implemented economically and cost-effectively. Polysun, the simulation software from Vela Solaris, provides the necessary results for the system simulation

EPRO Engineering, headquartered in Gümligen, Switzerland, specializes in the planning and implementation of holistic, sustainable solutions for heating, ventilation, air conditioning, refrigeration, sanitary, electrical, building automation and building climate control. The Sustainable Building division integrates all “classic” building technology trades into a whole and impresses with well thought-out solutions. The knowledge of around 50 employees is skillfully combined depending on the project. The use of modern tools is central to this and the Polysun simulation software is key to a holistic approach. This enabled a convincing solution to be found for planning the energy supply.

EPRO ENGINEERING impresses with transparency in planning

The new water supply plant in Ipsach will produce drinking water for 70,000 people in the Biel/Nidau region in the Swiss canton of Bern. The existing (old) water supply plant has served its purpose for almost 50 years and is being replaced by a new one in order to meet the increased requirements of a modern water supply system. For the water supply plant near the Lake Biel, the question arose as to how the heat supply could be sensibly provided in the future. The engineering firm EPRO, which is responsible for the planning and implementation of the HVAC and building services, was commissioned to do this.

Figure 1 – The water supply plant in Ipsach supplies drinking water for 70,000 people in the Biel region, in the Swiss canton of Bern

A key requirement for the future energy supply is that the waste heat from the existing emergency power and ozonization systems is used to cover the heat requirements for space and hall heating, domestic hot water and for industrial processes at different temperature levels. Two old lake water basins are available for storing the thermal energy.

In the first phase of planning, EPRO analyzed the annual supply profiles together with the customer in order to obtain a realistic estimate. The next step was to estimate the heat input from the emergency power and ozonization systems throughout the year. In a third step, the heat consumers and sources were shown in detail in the Polysun simulation software. The large thermal storage tanks and the use of a 150 kW heat pump as a backup system were also taken into account in a comprehensive overall analysis.

Figure 2: Illustration of the energy supply system in Polysun to define the optimization potential

The analysis of the energy supply system in Polysun revealed various optimization options:

– Additional consumers can be integrated, as the heat input clearly exceeds the heat output.

– Ideally, domestic hot water should be provided by a heat pump boiler.

– The dimensioning of the heat pump can be reduced.

– There is also potential in the dimensioning of the storage tanks.

In the next phase, EPRO simulated the optimization options – again in Polysun – checked the planning principles in detail and prepared them for a sensitivity analysis to ensure a reliable energy supply even with very conservative assumptions for waste heat.

Finding the optimum: Creating transparency with simulation

As the project progressed, EPRO worked with the project team to gradually tap into the optimization potential. Additional heat consumers were integrated into the energy supply. For example, the originally planned electrical temperature control of the emergency power systems was converted to thermal temperature control and heating of the factory space was planned.
A conservative scenario was used in a sensitivity analysis for the heat input of the ozonation plant. The increased energy demand of 150 % and reduced heat input of 63 % was updated in the Polysun model and the simulated system was significantly reduced in size – only one instead of two storage tanks and a heat pump with an output of 50 kW instead of 150 kW. The simulation showed that the energy supply can be reliably ensured all year round even with the reduced system size. The second storage tank will assume a redundancy function.

The solution is ecologically and economically convincing
The use of simulation in the planning phase means that the energy supply of the water supply plant in Ipsach can now be made significantly more efficient:

  • Waste heat utilization was increased by 150 %
  • The installed capacity of the heat pump was reduced by 66 %
  • A savings potential of around 30 % was identified for the storage volume.

This also saves the budget with substantially lower investment and operating costs.

Abbildung 3: Systemoverview of the water supply plant in Ipsach, Switzerland

Project cornerstones



Energy system components in the simulation model

Different energy generator and consumer profiles at different temperature levels, heat pump, storage tank

Services offered by Vela Solaris

Training for Polysun Designer users at EPRO for the independent creation of simulation models

Result with software Polysun

Convincing solution for supplying heat to thewater supply plant in Ipsach, Switzerland, with a significant increase in efficiency and cost reduction.


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Integrated planning of energy systems – Simulation software for the holistic evaluation of energy system variantsIntegrated planning of energy systems

Published in: Computer Spezial (01/2024)

With the increasing complexity of construction projects, a holistically efficient energy system can usually only be mapped precisely and across all sectors with the help of simulation software. In an article in Computer Spezial, the company Getec highlights the successful use of the Polysun simulation software in practice: “As an energy service provider, our calculations must of course be absolutely reliable: How much electricity from the generation system goes into the heat pump; how much does the customer use directly? How much of it is fed into the grid? How does it interact with the photovoltaic system? In some cases, very complex circuits are created that we have to map with a high degree of accuracy. That’s why it was clear to us that spreadsheets had had their day. We needed an adequate planning tool.”

Click here for the full article from Computer Spezial (01/2024, in german): Link

Vela Solaris at Renewable Energy Exhibition in Japan

The Renewable Energy Exhibition in Tokyo took place from January 31 to February 2, 2024 and we were pleased to be represented as an exhibitor together with our Japanese partner Desun Tech. The exhibition provided a comprehensive overview of the latest trends and developments in the renewable energy sector.

The main trends that became clear at the fair were impressive:

Japan is aiming for climate neutrality by 2050 and this was clearly evident at the fair. Government institutions, which are pursuing projects at regional and municipal level, are looking intensively for solutions. The focus here is particularly on the expansion of photovoltaics. Offshore wind power is also becoming increasingly important. The possibilities of making greater use of geothermal energy and biomass as energy sources were discussed controversially.

Particular attention was paid to districts:

Renewable energy solutions are planned and implemented with a strong focus on districts. The stand of the city of Ishikari in Hokkaido, which is located around 15 km from Sapporo, was particularly impressive. The bay area of Ishikari is home to large data centers that depend on a reliable energy supply. In future, this is to be ensured 100% by a mix of wind, biomass and photovoltaic systems.

Simulation in the planning stage:

The number of visitors grew steadily over the three days and the crowds, especially on the last day, were impressive. We were pleased to be able to make many new and interesting contacts. There was particularly great interest in the use of Polysun in the planning of energy systems for buildings and districts. There are no comparable providers in Japan yet, and the potential for innovative solutions is enormous!

SuWoTec and ANT

SuWoTec and ANT

SuWoTec together with ANT provide a circular system approach to the Dutch market, solving the challenges of designing and running energy systems in a sustainable way.

Pictures: iStock

One of the main challenges in the Dutch market today, is the lack of storage capacity for the surplus of solar energy production. SuWoTec together with ANT are focusing exactly on this challenge.

The Dutch company SuWoTec was founded in 2016, with the goal to provide sustainable energy solutions to the market. As its founder, Mr. Lammert de Wit explains: “Our solutions stand for a circular system approach, solving the challenges of designing and running energy systems in a sustainable way.”

The challenge

One of the main challenges in the Dutch market today, is the lack of storage capacity for the surplus of solar energy production. In 2022, the solar production of electricity increased by 46%, covering around fifteen percentage of total electric power production in the Netherlands. This trend will continue strongly with an estimated installation of around 4GW of solar power annually through 2028. While this is good news for decarbonizing the energy production, the electricity grid is not capable to transport the huge amount of electricity produced on sunny days. Therefore, energy suppliers have drastically reduced the feed-in tariffs, they are paying solar panel owners, sometimes even cutting off photovoltaic modules from the grid. Apart from grid improvements, new solutions to store electricity are urgently needed, to operate solar energy systems profitable and in line with grid capacity.

The solution

The projects of SuWoTec are focusing exactly on this challenge. For a broad range of buildings, innovative energy systems are planned, combining the solar production with thermal and electrical storage systems. Partnering up with the company ANT (Accelerating Natural Technologies), several projects following this integral planning approach are being carried out.

One example is a Boutique Hotel in Texel, where electricity consumption peaks exceeded the maximum contracted capacity, while nominal consumption levels were well within capacity. SuWoTec together with ANT were asked to find a solution, that reduces the peak energy consumption and production and at the same time increase energy consumed at the local level. The support of a battery during peak consumption reduced overall capacity within allowable limits, a method known as peak-shaving. Various battery capacities were modelled in the software Polysun to optimize the configuration of the new energy system.

Based on the positive project outcome, SuWoTec and ANT are now taking on even more complex projects such as whole chalet parks, considering the local PV production, electric vehicles and integrating a suitable battery system.

To design these innovative energy systems, SuWoTec together with ANT relies on the software Polysun from Vela Solaris. With Polysun, the desired energy system can be designed including even the most innovative energy system components, and the operation can be simulated throughout the year. Polysun gives insight, which option convinces in terms of energy efficiency, dimensioning of the components and the energy self-sufficiency level reached.

Mr. Jan Rolf van den Berg from ANT uses Polysun frequently, to answer relevant design questions. He especially appreciated the support received from Vela Solaris, when starting out with the software Polysun: “The individual training sessions were very helpful in mastering all relevant aspects of the program, such as defining the control logics of an energy system.”

Project cornerstones


  • SuWoTec
  • ANT (Accelerating Natural Technologies)

Business field

  • Providing sustainable energy systems to the Dutch market.


  • Finding optimal solution to reduce the peak energy consumption/production and at the same time increase energy consumed at the local level.

Result with software Polysun

  • Optimal sizing and integration of battery system, including the battery charging and discharging logics with regards to local PV production.
  • Limiting peak load and peak production in accordance with grid capacity.


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Energy solutions at GETEC

Energy solutions at GETEC

Polysun supports the planning and simulation of sustainable and economical energy solutions at GETEC

Pictures: ©GETEC

Easier to implement standards, enable controllability and comparability of projects.

GETEC is a leading partner to industry and the real estate sector for intelligent, efficient and green energy solutions in Europe. The promise “We have energy for more” is the guiding principle for over 2,400 employees who use excellent engineering know-how, outstanding control competence, high speed of action and proven sustainability expertise to navigate customers through an increasingly complex energy world while reducing their environmental footprint. With 11,500 plants generating more than 5.4 GW of thermal energy, GETEC is active in a total of nine countries from its four regional platforms in Germany, Switzerland, the Netherlands and Italy, generating sales of 1.6 billion euros in 2022.

The challenge
First and foremost, Polysun was to initiate an important change process at the subsidiary GETEC Wärme und Effizienz GmbH. GETEC Wärme und Effizienz develops sustainable energy concepts and specializes in projects for the real estate industry. These include residential buildings above a certain size, entire neighborhoods, hospitals and shopping centers. “As we all know, it is becoming increasingly complex to be able to offer our customers suitable solutions,” says Volkmar Börner, the GETEC manager responsible for software selection. In order to maintain an overview at all times for projects of this magnitude, the company, which operates throughout Europe, quickly realized that Excel spreadsheets were not the tool of choice.

“As an energy service provider, our calculation must of course be absolutely reliable: How much electricity from the generation system goes into the heat pump; how much does the customer use directly? How much of it is fed into the grid? How does it interact with the photovoltaic system? In some cases, very complex circuits are created that we have to map with a high degree of accuracy. That’s why it was clear to us: spreadsheets have had their day. We needed an adequate planning tool,” says the expert.

The specific question that GETEC’s managers asked themselves was therefore: “Should we have individual programming or would it be better to purchase suitable software directly? However, it was clear to us that we would have to plan a good two years of development time for individual software. In addition, the cost of maintaining the software solution in the ongoing process should not be underestimated,” says Börner.

The solution
For these reasons, GETEC started a multi-stage software selection process with various software providers, from which Polysun emerged as the tool of choice. The energy company was particularly convinced by the graphical display options, the many variables that can be run through with it, and ultimately the wide range of functions. Börner comments, “Polysun has, for example, achieved a clear first place ahead of all competitors in the hydraulics area, so control strategies can be better displayed.”
Within GETEC Wärme und Effizienz GmbH, Polysun is now used across departments to simulate and plan different variants of power and heat supply, and then to enter them into a coordination process with other departments. A dedicated working group exchanges information on the optimal mapping of GETEC’s standard hydraulics in Polysun and is constantly expanding its internal expertise. “In the process, colleagues create comprehensive simulation variants, which they then coordinate with the various departments and in this process also receive feedback that is very valuable for all of us. We very much appreciate these internal customization options of the Polysun software,” says Volkmar Börner.

The result
As curious as it may sound, the positive consequences of using the software began even before the software solution was actually used. Michael Blümel, project engineer at GETEC Wärme & Effizienz GmbH clarifies: “This approach helps us a lot to enable uniform project simulation and planning.” This means: the first concrete added value of Polysun is that within GETEC there is thus a uniform tool for colleagues, which creates standards, as well as enables a clear controllability and comparability of projects.

Project cornerstones


GETEC Wärme und Effizienz GmbH, a subsidiary of G+E GETEC Holding GmbH with 50 locations in nine european countries.

Business field

Energy services company in a group structure with a large number of companies offering a broad portfolio of energy services in the liberalized energy market


  • Highly diversified group portfolio must be able to adapt to dynamic market conditions (more renewables, sector coupling)
  • Planning with spreadsheets not sufficient
  • Uniformity of planning in actual state endangered

Result with software Polysun

  • Uniform planning in the real estate segment
  • Innovative use of the software (expert panels with their own standards)
  • Convincing customer presentations
  • Accuracy in planning and simulation
  • Significant improvement in process quality


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TESVOLT Project planner:


Quick and easy from technical design to order!

pictures: ©TESVOLT

TESVOLT partners can use the project planner to design battery and EMS systems from the battery storage system provider online and order them right away. The TESVOLT Project Planner is based on the Polysun API for system configuration.

TESVOLT AG, based in Lutherstadt Wittenberg, Germany, is a manufacturer specializing in battery storage for commercial and industrial applications. “Bringing affordable, clean energy to every corner of the world – that’s our goal. Even to places where people don’t have access to the power grid.” With its mission to create affordable energy solutions, TESVOLT offers important advantages, especially in the current market environment. For example, investing in battery storage is particularly worthwhile for companies with a solar or wind energy system, as it allows them to increase the proportion of electricity consumed from their own systems and thus become largely independent of rising electricity prices. The expensive load peaks can also be capped by appropriately smart control of battery charging and discharging.

TESVOLT focuses on digital processes and offers an online planning tool for partners:

TESVOLT has relied on digital channels for marketing its storage solutions right from the start. This is also in line with the company’s agile mindset.

Since the beginning of 2022, TESVOLT partners have been able to use the project planner to configure storage solutions online in six steps, select the appropriate storage, create a list of materials, and trigger an order.
Today, a rapidly growing number of orders are processed digitally. Currently, the digitally processed share is around 90% of all orders placed.

Storage system is configured based on the Polysun API:
TESVOLT evaluated various possibilities to carry out the storage design digitally and as automatically as possible on the basis of the project specifications. With the simulation software Polysun, a field-proven simulation software was available, which could also be flexibly integrated into the TESVOLT solution via an API interface. In a joint project team consisting of employees from TESVOLT, Vela Solaris and the web design partner Nagarro, the TESVOLT project planner was developed step-by-step in a very short time. For this purpose, various system templates were defined in Polysun, which depict TESVOLT’s storage solutions in combination with photovoltaics over the entire year and simulate the energy flows in detail. Various use cases with the corresponding control logic were mapped as EMS in Polysun, e.g. self-consumption optimization, peak load capping or multi-use. The project-specific data, such as consumption, location and PV system, parameterize the Polysun templates and provide meaningful simulation results, which are used for the selection of the optimal battery storage as well as for the generation of the result report.

Intuitive solution for TESVOLT partners

The TESVOLT project planner supports the user in configuring the storage system by providing planning aids and showing the added value of the selected solution at a glance. Thus, the most important key figures on self-consumption quota, degree of self-sufficiency, saved electricity costs and CO2 reduction are shown. In addition, the interaction of battery, PV and consumption is also visually displayed as a daily, weekly or annual progression. The solution is now being continuously optimized and further developed in an agile project setup.

Key aspects:



Energy system components for simulation

  • battery storage
  • EMS
  • photovoltaics

Services provided by Vela Solaris

Provistion of simulation model based on Polysun API. Simulative mapping of TESVOLT storage solutions and EMS systems


Best-in-class project planner for TESVOLT partners. Great time savings in the sales, planning and ordering process.


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New building ProfiCamp Eintracht Frankfurt:


Mainova provides sustainable energy for the Eintracht family!

pictures: ©Eintracht

Mainova optimizes the operation of the state-of-the-art plant technology of the ProfiCamp Eintracht Frankfurt and relies on the simulation software Polysun.

Mainova supplies more than one million people in Frankfurt am Main with electricity, gas, heat and water and is a convincing high-performance partner in the operation of sophisticated plant technology. The focus is on decentralized and environmentally friendly energy generation with high plant efficiency and optimal energy use. The professional soccer club Eintracht Frankfurt has therefore decided to place the energy supply of its new ProfiCamp in the hands of Mainova. The new ProfiCamp comprises the 800-square-meter fitness area, including a whirlpool, and a 400-square-meter administration building, including a 120-seat staff restaurant. The building standard corresponds to a passive house and thus to the most modern requirements.

Mainova defines the optimal operation of the energy systems:
The experts at Mainova analyzed the existing energy system in detail, with the aim of ensuring efficient use of the renewably generated energy. The system concept for meeting heating and cooling requirements consists of seven heat pumps (three air-to-water heat pumps with a cumulative output of 450 kW and four brine-to-water heat pumps with a cumulative output of 240 kW), solar thermal collectors on 107 square meters of roof surface, a geothermal collector and a gas boiler. A particular challenge was the prediction of the user behavior, which has large demand peaks due to the training periods. In addition, the geothermal collector is located in a water protection area with corresponding requirements for the cooling of the ground.

The Polysun software is used to test operating variants in a target-oriented manner:
Mainova’s experts use the Polysun software to map the existing system with all its components and to simulatively define the optimal operation. The goal was to use the gas boiler only to cover a few hours. In a first step, a simplified rough simulation was carried out in Polysun and the generators were combined in a meaningful way. This allowed a quick comparison of variants of different control concepts and a basic decision in this respect. In a second step, the simulation in Polysun was refined based on the selected control concept and the generators were mapped in detail. In addition, different consumption scenarios were stored and the robustness of the energy supply for the provision of heat and cold throughout the year was checked. The simulation experts from Vela Solaris supported the simulative mapping in Polysun by setting up the corresponding hydraulic schemas.

Polysun system template

The system technology supplies renewable energy during operation:
In the meantime, the new ProfiCamp has been occupied by the Eintracht family and is reliably supplied with renewable energy by Mainova. The plant will be monitored over all operating points for two years and further optimized with the help of Polysun. Mainova also expects to be able to identify and eliminate the causes more quickly in the event that the actual operation fails to meet the target state, thanks to the simulation with Polysun.

Key aspects:


Mainova AG

Energy system components for simulation

  • Solar thermal
  • heat pumps (air-water, water-water)
  • geothermal collector
  • gas boiler
  • technical storage tank for heating and cooling energy
  • hot water tank

Services provided by Vela Solaris

Provision of base model of simulation with Polysun software considering Mainova requirements and model refinement.


Successful definition of operational control, taking into account the efficient integration of different producers as well as constraints related to water conservation.


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Customers ask us: Post # 1

To what extent does the installation of a heat pump reduce the gas consumption of a building?

This is a question frequently asked by our customers: engineers who plan and advise on energy systems for buildings and districts.

The answer varies depending on the project. In a specific project example, the answer is 65% (reduction of annual gas consumption from 27.4 MWh to 9.5 MWh, shown here over the course of a year).

Comparison of energy supply options with Polysun

Getting this answer took us little time and the result is precise! With our simulation software Polysun energy systems are planned reliably and in a few steps.

Do you have this or another question about your energy system project?

Please contact us:

or get to know our software Polysun at a free webinar:

EnBW Contracting

Demonstrating reliable energy system options convinces B2B customers

EnBW Contracting

EnBW Contracting plans future-oriented energy supply concepts for the housing industry with Polysun.

When it comes to energy, more and more business customers are turning to an experienced specialist offering a contracting partnership. The reason is obvious: an optimized energy supply concept and the long-term predictability of energy costs are more than ever the decisive keys to success. Because these two factors provide customers with security and thus competitive advantages on the market.

EnBW Contracting GmbH has adopted this approach and is leading the way innovatively. The wholly owned subsidiary of the energy group EnBW Energie Baden-Württemberg AG (EnBW) offers customers reliable solutions tailored to individual project characteristics.

EnBW Contracting focuses on supplying energy to industrial customers, municipalities and the housing industry. Demand-driven energy supply concepts and professional operational management enable this target group to concentrate on its core business.

Olaf Kleineschallau, Team Leader Planning & Realization at EnBW Contracting, and his team are responsible for the planning of these energy concepts, from the initial idea to the comparison of options to the detailed planning of the best solution and the subsequent realization of the plants. In view of the increasing complexity of projects, there was a greater need to supplement the self-programmed design programs, which had been steadily optimized over the years, with a standard software solution. Olaf Kleineschallau explains, “As a supplement, we were looking for a tool that could handle multiple energy technologies and always provide us with the best possible option for the customer.”

After an evaluation phase with various software solutions and extensive tests in real operation, EnBW Contracting decided on Polysun from Vela Solaris.

The solution
For the application field “residential area from 100 residential units” with efficiency standard KfW 55, different supply options with gas, air-to-water and earth-to-water heat pumps as well as solar thermal were defined in the Polysun software. These templates are now used right from the start. As requested, the experts at EnBW Contracting can also use the software from Vela Solaris for the most complex simulations. For example, they use it to design PV in combination with battery storage for own consumption optimization and simulate the combination of different heat generators from different sources – earth, water, sun, air.

The result
EnBW Contracting’s customers have a specific useful energy requirement for which they can obtain combined supply variants in every conceivable form.

“For example, solar energy use in combination with other energy sources,” says Olaf Kleineschallau. “No matter whether it’s a complex interconnection, different energy sources for heat pumps or even solar thermal energy – we can plan what seems conclusive to us and our customers with Polysun.”

“We also very much appreciate the competence of Vela Solaris’ technical support, which is always available to us very quickly. This allows us to continue working quickly,” adds team leader Olaf Kleineschallau.

Key points

At a glance

  • Customer: EnBW Contracting GmbH
  • Sector: Energy supply contracting in the form of the provision or supply of heat, steam, cooling, compressed air, electricity from CHP and the operation of the associated facilities, with particular emphasis on renewable energies
  • Location: Stuttgart


  • Increasing need to supplement the self-programmed design programs, which have been continuously optimized over the years, with a standard software solution.
  • It must be possible to map all technologies, especially the combination of different energy technologies.
  • It must be possible to show the best possible option transparently.


  • Polysun Designer
  • Service Vela Solaris: Creation of standardized energy system templates for use in Polysun.


  • Special use cases of different energy sources for heat pumps and use of solar thermal energy can be solved with Polysun.
  • The reliability of the calculated options is guaranteed
  • EnBW Contracting convinces its customers by showing valid simulated options and a supported recommendation for the best option.

Contact us to learn more about what our software Polysun and our simulation experts can do for you!

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PCM and latent thermal storage successfully simulated with Polysun

A latent thermal storage system with PCM capsules is simulated in Polysun in an advanced thesis at HSLU.

In his thesis at the Lucerne University of Applied Sciences and Art (Switzerland), Mr. Markus Lacher tackled the problem of simulating latent thermal storage systems with PCM capsules using the Polysun software from Vela Solaris.

First, the system of latent thermal storage was analyzed in detail to determine the different influencing parameters. Then, a parameter analysis was performed on the fluid properties specified in Polysun to understand the calculations of the storage temperatures as well as capacities in Polysun. The next step was to program three different PCMs and test the PCMs through an experimental simulation. Then, the programming of an experimental memory in Polysun was done, giving the opportunity to validate the memory design. Finally, the simulation of an energy system of a single-family house took place.
The experiment was successful: “The simulations showed that both PCM and the latent thermal storage in Polysun can be simulated with the given components. The simulated capacity of the experimental storage tank of about 7.97 kWh corresponds quite closely to the measured capacity of 7.9 kWh or the temperature calculated 8.1 kWh.”

Find here the complete thesis (in german): link

Vela Solaris congratulates on the exciting work!

Are you interested in learning more about the possibilities of simulating PCM and latent thermal storage with Polysun? Feel free to contact us at

campus of Lucerne University of Applied Sciences and Art (Switzerland)

With the Polysun software from Vela Solaris you can rely on a multi-practice simulation of your energy system with reliable results in terms of functionality, energy efficiency and profitability – from single-family homes to districts, worldwide and for all market-standard technologies.

levelup with Polysun

TH Rosenheim competes again in Solar Decathlon Europe 21.

There are many ideas for sustainable urban development. The crucial thing is to follow up the ideas with action. The Solar Decathlon Europe 21 (SDE21) therefore has the motto “Design – Build – Operate”. University teams from all over the world come together to design, build and operate solar houses with a neutral or even positive energy balance.

levelup with Polysun

After the great success at the Solar Decathlon Europe 2010 as “Vice World Champion in Solar Building”, the Rosenheim Technical University of Applied Sciences is taking on the challenge again. The levelup project at the TH Rosenheim is currently being driven forward by an interdisciplinary project team from various courses of study and faculties. At their side are about 20 advising professors from different courses of study. “levelup” stands for a modular, flexible addition in lightweight wood construction, adaptable to almost all 1950s to 1970s buildings. This creates an innovative solution for redensification in cities that can be applied to the largest proportion of Germany’s building stock of multi-family houses.
levelup relies on a renewable energy supply: The levelup is to be brought to an energy-plus level, which also includes the supply of the existing building stock over its life cycle. Photovoltaic modules for solar power generation on the entire facade and on the roof contribute to this.
For the planning of the solar energy system, the interdisciplinary levelup team relies on the Polysun simulation software from Vela Solaris. The energy production can be simulated precisely over the entire life cycle. With Polysun, the students succeed in gaining planning reliability and verifying whether the requirements regarding the energy-plus level are achieved.
The competition will run until the summer of 2022, when the houses built will be evaluated and awarded prizes. So the levelup team is in the middle of its work! The whole Vela Solaris team keeps its fingers crossed!
Learn more about the levelup project: link

Demand for commercial storage for peak shaving is on the rise.

pv magazine updated market overview of commercial and grid storage systems. Polysun is mentioned as a simulation software for storage integration.

The demand for commercial storage for peak shaving is on the rise. pv magazine updated its market overview providing interesting insights: Manufacturer prices decreased by an average of five percent. The market is still small in absolute numbers – but with a strong trend towards growth. That is what we at Vela Solaris are also experiencing: The demand for simulation of energy systems with storage capacities is increasing! With Polysun it is possible to show the impacts of storage integration on the increase of solar self-consumption, peak-shaving for grid fee reduction or on the integration of electric vehicles. We are pleased to be the only simulation software listed in pv magazine’s current market overview.

Learn more about the market overview of pv magazine:

SunPeople project builds energy simulation platform – using the Polysun API

The Interreg FCE SunPeople project aims to increase the development of a decarbonised heat energy service in the residential and commercial sectors. The project’s objective is to demonstrate and test on 15 sites, in Plymouth and Lorient, a cost-competitive, sustainable heat energy service based on heat pump and solar technologies. This service will enable to reduce carbon emissions on these sites an estimated 62.8 tons of carbon over a one-year contracting period corresponding to the project.

The service will rely upon a building energy simulation platform to scale up the zero-emission heating industry. The simulation of building energy schemes will be carried out using the Polysun simulation by Vela Solaris in the cloud (Polysun API).

comparing energy systems

The SunPeople project including the reference simulation platform approach relying upon Polysun software was introduced by Vela Solaris and ALOEN at this year’s conference of the European Heat Pump Association (EHPA) on Digitalization in the H&C industry, on March 9 2021.

Missed it? Access the slides here.

Further information on the Interreg FCE SunPeople project: Link

Polysun is accredited by Minergie

Our simulation software Polysun is now officially accredited by Minergie for the calculation of PV yields.

Minergie is committed to quality assurance in the planning, construction and operating phases of buildings in Switzerland. The three building standards Minergie, Minergie-P and Minergie-A already set clear requirements in the planning phase with regard to quality, efficiency and comfort. Today, depending on the region, 10% to 25% of new buildings are planned according to Minergie.

For the verification of the PV yield, Minergie wants to ensure a comprehensible and uniform verification of the Minergie applications. We are very pleased that our simulation software Polysun is now officially accredited by Minergie as a calculation tool for the verification of PV yields.

Polysun takes into account the efficiency of the modules, the orientation and size of the plant, the exact location and relies on current weather data for the PV yield forecast. With Polysun, even higher yields than the standard value of 800 kWh/kWp can be claimed. In Switzerland, yields of 1,000 kWh/kWp and more are possible at most locations. It is therefore worthwhile to calculate PV yields with Polysun and use them for Minergie applications.

Source: Minergie

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Polysun goes BIM: The new Polysun release increases planning quality!

The actual software release of Polysun makes the use of simulation of energy systems in digital planning even easier.

The digital simulation of energy systems generates a clear added value: various aspects are tested at an early stage and the quality of the planning increases. This significantly reduces investment and operating costs.  The current release of Polysun makes the use of simulation in digital planning even easier: relevant information on the current planning status is available at the push of a button. The fulfilment of set requirements for the energy system is immediately visible. Data import and export is automated and supports interdisciplinary teamwork. This also enables, for the first time, the seamless integration of energy system simulation in BIM projects.  Simulation results can be generated and validated even faster. As a digital twin, the planning data is reproducibly available and generates added value right up to the operating phase. This makes quality control easy! Our development partner, the engineering services company Amstein & Walthert confirms: “This makes planning energy systems a pleasure! We were able to test Polysun-BIM on a concrete construction project and see great potential in using the software!”

Highlights of the Polysun software release, version 12, with Polysun BIM Add-On:

  • Polysun-BIM supports automated data exchange. Meteorological data, heating load data and simulation results are thus available to the project team at the desired location at all times.
  • The data import is subject to an automated quality check. Implausible and incomplete data are recognized immediately.
  • Key performance metrics (KPM) from the construction project are defined for the energy system in Polysun on a project-specific basis. The achievement of set KPMs and deviations are available at any time at the push of a button.
simulation software in BIM projects for designign energy systems
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Clever use of simulation in BIM projects: This makes planning fun!

BIM (Building Information Modeling) raises high expectations for time and cost savings and for improved planning reliability. In a joint project by Amstein + Walthert with Vela Solaris and with the financial support of EnergieSchweiz, it was examined how concrete added value can be created in practice. A decisive success factor is the combination of simulation and BIM. The corresponding use case will be made publicly available through Bauen Digital Schweiz.

The demands on buildings are increasing: With consequences for planning

Today’s buildings must meet increasing requirements: They should offer a high level of comfort, convince with modern architecture and at the same time be energy-efficient and profitable to build and operate. For planning, this means that different disciplines must work closely together to ensure high planning quality. For this to succeed, two things are essential:

  • Define targets at an early stage:  From the client’s point of view, the objectives for the overall project must be available as early as possible and translated for the individual disciplines from architecture to building services engineering.
  • Enabling flexible changes to targets: If the requirements of a project change, the relevant information must be made available to the project team immediately and reliably.

This is the only way to ensure that deviations from targets are recognized by the project team and addressed at the lowest possible cost.

Simulation as a success factor for reliable planning

This is exactly where dynamic simulation of energy consumption and the satisfaction of demand by energy systems comes in. In time steps down to a second basis it is simulated how the planned energy system behaves during operation: From the heat stratification in the storage tank to the use of the solar system’s electricity production.

By means of simulation, it becomes clear at the push of a button whether a changed initial situation – caused by new requirements during the project – will lead to a deviation from the target specifications. If, for example, the usable roof area is reduced or the building use is changed, it can be simulated immediately what this means for energy consumption and energy system technology and whether adjustments are necessary. This increases the planning reliability and thus the confidence of the client in the planning.

But what does this mean in connection with BIM? What are the advantages of linking BIM with simulation? And how can processes and tools support this?

Amstein + Walthert and Vela Solaris are taking the next step. In a joint project, supported by EnergieSchweiz, the planning process was expanded in the area of model-based performance optimization and the Polysun simulation tool for process support was optimized.

Model-based performance optimization (MPO): BIM and simulation cleverly linked

The use case “Model-based Performance Optimization – MPO” from Amstein + Walthert combines the specialist areas of building simulation, energy system simulation and building services engineering planning. The main focus here is on enabling planning adjustments at any time and in frequent iterations – consistently across all specialist areas.

The MPO skilfully combines planning with simulation, taking advantage of the benefits of the BIM methodology: planners, simulation and BIM experts and project managers at Amstein + Walthert as well as experts for energy system simulation from Vela Solaris have contributed their knowledge to the MPO. The most efficient workflows and corresponding interfaces between different departments were jointly defined. This was done with the aim of enabling the seamless exchange of simulation results and thus increasing planning reliability. As a result, the MPO automatically links the required information and simulation results, documents changes and makes planning work in the BIM project more transparent. Frequent iterations of the planning and simulation results are now even easier to perform and facilitate efficient work for all project participants. 

The MPO has been successfully tested on projects currently in planning. The project team is convinced of the gained process efficiency and quality.

The Open-BIM-based use case will be published on Digital Switzerland and buildingSMART Switzerland. The MPO method is thus available to all interested parties, can be continuously improved and is easy to use.

Smart processes need smart tools

The simulation software Polysun from Vela Solaris has been successfully used by Amstein + Walthert for years for the simulation of energy systems for buildings and districts. In the joint project described here, Polysun was made BIM-capable and thus ideally supports the MPO process.

Open-BIM interfaces enable a largely automated data exchange. Simulation results are thus available to the project team at the desired location at any time and are transferred to the BIM model of the building services engineering. As a result, only time for planning has to be spent if deviations from the target values occur – the planning time is significantly reduced. Polysun also provides digital support for the evaluation of the achievement of building services engineering targets.

All simulation results remain transparently documented with Polysun BIM and provide added value right through to the operating phase – for simple quality assurance.

Energy system simulation is easy to use

With the new MPO and Polysun BIM from Vela Solaris, it will be much easier for simulation experts and planners to accurately design systems for today’s buildings. Relevant information is exchanged digitally. Tedious data quality checks are no longer necessary.

System support makes deviations from targets immediately transparent and the expertise can be directed to the essential points – for a high level of planning reliability that is convincing. This makes the use of simulation in planning a pleasure!

We would like to thank Amstein + Walthert for the great cooperation and EnergieSchweiz for the project support!

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