Interview with Eng. Armyanov for the magazine Gradat – Office Buildings

In April, issue 2 of the magazine Gradat was published. The theme of the issue was “Office Buildings.”
We present to you the interview of Eng. Yuliy Armyanov with the magazine’s team.

• Eng. Armianov, you have been working with heat recovery ventilation for many years. How has this segment of ventilation and air conditioning systems developed?

Yes, I recently realized that I started working as an HVAC designer exactly 40 years ago, and for nearly 35 years I have been involved with heat recovery ventilation systems. In the beginning, these systems were considered exotic. Few countries and organizations ventured into researching these solutions. Over time, they became popular, and today they are mandatory in many European countries. There are numerous benefits to installing heat recovery ventilation for building occupants. Clean, fresh, and filtered air is supplied to the rooms, while the exhaust air is expelled, using its energy to warm the incoming fresh air. This leads to improved quality of life, reduced risks of illnesses and allergies, and last but not least… reduced heating costs for fresh air, as well as a smaller carbon footprint for buildings.

Heat recovery ventilation has become mandatory for EU countries and Switzerland. This has led to an increase in sales of these types of systems and the phasing out of old air supply systems without energy recovery. Nowadays, every HVAC project must include such a system. I believe the trend of increasing sales of heat recovery ventilation systems will continue, complemented by investor demands for more advanced intelligent controls.

• TANGRA” is the first manufacturer in Bulgaria of high-efficiency energy-saving systems for ventilation and air conditioning installations. What are the latest innovations in your products and engineering solutions??

 In the early 1980s, when I began working on energy saving in ventilation systems, this was almost unknown in Bulgaria because the price of electricity was just 3 stotinki per kWh. In 1992, we produced our first heat recovery unit. At that time, we were pleased with an efficiency of 45-50%. Gradually, with our team, we worked to improve the efficiency of heat recovery ventilation, and today our plate heat exchangers achieve up to 85% energy recovery (EN308). For this work, we were consecutively awarded by the German-Bulgarian Chamber of Industry and Commerce and by President Rosen Plevneliev. Today, our products are successfully sold in more than 15 European countries.

 

Hybrid air handling units with two-stage heat recovery (integrated heat pump) are becoming increasingly popular both in Europe and Bulgaria. Their efficiency reaches up to 92%. These results were established after extensive testing by our engineers and specialists from TUV Rheinland. Only then did we allow these units onto the market and could confidently guarantee what we offer.

 

Since the end of 2017, in addition to VRF systems powered by electricity for compressor operation, we also offer VRF systems running on natural gas. These are relatively new to Bulgaria, but we represent a Japanese corporation founded in 1912 that has been involved in energy systems for heating and cooling since 1987. Their experience is very valuable to us. The popularization of these systems is closely linked to the prices of primary energy sources — natural gas and electricity.

 

As the representative of Johnson Controls HITACHI for Bulgaria, we promote the latest product range from the corporation — the Set Free Ʃ VRF systems and the Verasys BMS platform. The outdoor VRF units are the most energy-efficient systems on the European market, thanks to the specific design of the evaporator section and being among the few that meet the requirements of the Ecodesign 2020 directive. The Verasys building automation system is developed to allow installers to intuitively build BMS solutions without the need to purchase expensive, widely known platforms.

 

•  What are the most correct — optimal — solutions for energy efficiency in office buildings?

There are several factors that determine comfort in a building. These include temperature, humidity, fresh air, noise, and so on.

 

Every investor, architect, and fellow designer sets the parameters of the building they start to construct together. The better the synergy between them, the better the building that will be built.

 

We offer even more — a financial and technological analysis of different ventilation, heating, and air conditioning systems. We assist in selecting the optimal solution to achieve the desired balance between capital investment and subsequent operating costs. This gives us peace of mind and confidence that once an office building is completed, its installations will provide a comfortable indoor climate, ensuring both investors and occupants are satisfied with the results at a reasonable cost.

 

Over the years, various systems and solutions have become popular. In the past, we more often installed water-based heating and cooling systems, while ventilation was based on central air handling units.
Later, direct expansion systems — VRF — began to replace chillers and heat pumps, and air handling units gradually gave way to compact, zonal, recuperative systems. This shift allows for easier subsequent leasing of different parts of the building while maintaining comfort throughout.

 

• By December 31, 2020, every public building in the EU was required to have a fresh air system with energy recovery. How is this implemented in Bulgaria and Europe?

 Yes, you are right. Every public building with a gross floor area (GFA) over 250 sq. m., according to Directive 27/2012/EU, must have a system for supplying fresh air and exhausting used air, and this system must recover waste heat.

 

This is also related to the “Europe 2020” program for reducing carbon emissions. Experts in Europe are well aware of the benefits and advantages of such systems. Since the residential building stock is more difficult to regulate, and office buildings in the EU are required to have such systems, work has begun on public and institutional buildings. This includes schools, kindergartens, universities, hospitals, municipal and government buildings. The idea behind implementing these systems is to provide a better indoor climate for occupants, while simultaneously reducing heating costs. We participate in such projects with our external partners, since other countries in Europe have been working on this topic for many years. In 2008 and 2009, we exported recuperative ventilation systems for schools in Portugal. Since last year, we have had similar projects for various schools in the Czech Republic. There, the funding comes from the state and European programs. When fresh, filtered air flows into the schools and kindergartens of our children, they breathe better and live in environments with fewer allergens and asthma triggers. Recuperative ventilation is extremely important and, in our opinion, an excellent capital investment that pays off in 2–3 years and provides tremendous benefits for the occupants of the ventilated spaces.

 

• What are the modern design solutions that should be applied in our country? What are your impressions of the construction sector in Bulgaria and the EU?

In Europe, a great deal of work is being done to improve product efficiency, develop integrated products with intelligent controls, and, last but not least, government institutions and the Council of Europe are working intensively on regulatory frameworks, directives, and standards. We follow these trends because they make good sense.

 

Our high-efficiency heat recovery units have long exceeded the efficiency requirements of regulations 1253 and 1254 valid for 2018. Currently, our units achieve efficiency between 76% and 85%, which gave us the confidence to start Eurovent certification. We will be the 11th company in the world to hold such a certificate, proving our efficiency and quality.

 

The TANGRA AHU air handling units are also in the process of Eurovent certification, as this is a product we successfully export to Switzerland, Poland, the Czech Republic, and the Balkan Peninsula countries.

 

In Bulgaria, new hospitals are being built and old ones are being renovated. Additionally, clean manufacturing facilities and food production plants, working with bacteria (bread, milk, meat, etc.), are being established. In these facilities, the use of hygienic air handling units is mandatory. There are two widely accepted standards — VDI6022 and DIN1946. These set requirements for manufacturers to ensure cleanliness and hygiene standards within the premises. I am proud to say that TANGRA is the only manufacturer in the country to have certified hygienic air handling units according to these standards, in cooperation with TUV Rheinland Germany. We have completed numerous projects, including hospitals and clean manufacturing plants.

 

Unfortunately, in Bulgaria, the construction sector often overlooks requirements and financial-technological analysis because the lowest price is the leading factor, which leads to compromises in quality. If a system is slightly more expensive but offers higher efficiency and meets the highest European standards, it will certainly pay off as an investment in the future.

 

• Could you please provide us with reference office buildings where your HVAC systems have been installed?

Certainly. I believe everyone takes pride in the projects they and their team have completed, especially when the investor is satisfied afterward. We have successfully executed numerous projects since 1989, but those clients who truly tested our capabilities and challenged us are perhaps the most interesting. Examples of such buildings include:

 

      – Capital Fort – the first skyscraper in Sofia. To ensure we could successfully execute the project, we even visited our colleagues during the construction of the Burj Khalifa in Dubai. They showed us the entire process—from the planning and briefing rooms to the installation work 600 meters above ground. The final meters we accessed via an external elevator.

 

    –  The administrative building of UniCredit Bulbank, which is divided into two wings. In the first wing, we installed a water-based cooling and heating system, as specified by the designer, while in the second wing, a direct expansion VRF system was implemented. Both wings are equipped with high-efficiency ventilation systems with energy recovery.

 

      – The design of the multifunctional building “Arco Towers” was also a challenge. Our projects were coordinated in 3D with every specialty and submitted for approval in the UK at ARUP. Today it sounds easy and almost everyone does it, but… this was over 10 years ago, when REVIT and BIM were almost unknown.

 

     – The multifunctional building of Geotrading, which we are currently completing, features multiple systems with integrated building management (BMS). The investor’s goal is to achieve the highest level of energy efficiency. The building is constructed according to BREEAM standards, and the systems include VRF, geothermal water-cooled units, recuperative ventilation, local extraction, and many others. All systems are controlled based on air quality and have built-in intelligent management. Besides being the contractor, we are also the HVAC system designers for the project.

 

In conclusion, I want to emphasize that heating, ventilation, and air conditioning systems serve the people inhabiting office buildings. The better the indoor climate we provide, the higher the productivity achieved. Energy efficiency directly impacts the financial results of the owner.