Increased energy efficiency requirements for ventilation and air conditioning systems effective from January 1, 2016.

Interview with Eng. Yuliy Armyanov, Managing Director of TANGRA – AV Ltd

Eng. Armianov, could you tell us about the changes in energy-efficient ventilation systems?

The efficient use of energy to maintain the indoor climate in buildings is becoming an increasingly recognized task for designers and builders. The updated regulatory framework, new insulation materials and technologies, as well as new types of window frames and door and window seals, have significantly reduced energy consumption for heating and cooling.

Gradually, we have turned buildings into thermoses.

When the coffee in a thermos stays hot and aromatic even after ten hours, everyone is happy—but living in a tightly sealed space is harmful and dangerous. For a person to live, they need to breathe, which means fresh air is essential.

Hardly anyone would imagine ventilating a modern building by simply opening the windows. This method is inefficient, costly, unhygienic, and often unacceptable. Clearly, fresh air must be supplied through mechanical ventilation. The amount of fresh air required per person or per square meter of a building is regulated by standards, which are roughly the same across European countries and the USA. Numerous studies confirm its significant impact on the health and productivity of building occupants.

In order for air to be supplied to the rooms, it must be filtered, heated in winter, and often cooled in summer. It turns out that in a modern, well-insulated and tightly sealed building, the energy required to condition fresh air can exceed the energy needed for heating.

For this reason, systems for recovering energy from exhaust air and gases (heat recovery or regeneration) have emerged and are continuously being improved.

Were these energy recovery systems easily adopted? Is there any regulated legislation in this regard?!

It took a lot of effort to convince people and prove that these systems are economically beneficial and environmentally friendly. Today, the discussion has definitively concluded. Energy recovery in ventilation and air-conditioning systems is moving from being optional to mandatory – BDS EN 13053-6.5.1:
All installations that supply fresh air and exhaust used air must have energy recovery systems.

What’s more! There is a clear trend toward technological solutions that allow energy recovery with an efficiency of over 80% (i.e., recovering more than 80% of the energy from the exhaust air).
Along the same lines, the regulatory framework is also evolving. European Commission Regulation (EU) No 1253/2014 requires:

A minimum efficiency (energy recovery effectiveness) of 67% from 01.01.2016, and 73% from 01.01.2018.

Another important factor affecting the efficiency of ventilation and air-conditioning systems is the electrical energy consumed by the fans. Given their continuous operation, including periods when there is no need to heat or cool the air, fans represent a significant energy consumer. Efforts are focused in two main directions:

• First – fans are designed to transport air while consuming less electrical energy.
• Second – fans must allow variable speed operation (i.e., the airflow rate can be adjusted according to the number of occupants or other parameters).

As a rule, installations are designed and implemented for maximum load, caused by factors such as the number of people, humidity, air pollution, etc. In actual operation, these extreme conditions are very rare. In most cases, the air required for ventilation is significantly less than the maximum.

1. Design airflow rate

2. Flow rate covering instantaneous needs

The shaded area corresponds to the energy saved for the preparation (heating or cooling) and transportation of the air.

Another key approach to increasing the energy efficiency of ventilation systems is free cooling. There are extended periods during which the outdoor air temperature allows it to be used as a cooling agent. For the city of Sofia, this amounts to more than 2,000 hours per year. This reduces the workload of the refrigeration unit and saves energy. To implement this idea, a short-circuit connection (By-pass) is installed in the recuperative ventilation units, which, under certain conditions, allows the fresh air to bypass the heat exchanger.

Okay, but every such complex ventilation system is expensive, right? What is the payback period for the investment?

After everything mentioned so far, it is very important to emphasize that energy-saving ventilation makes a lot of sense both for health and economically!

Initially, the investor allocates funds for the installation. It is assumed that the system will operate for at least 10 years with proper maintenance. During this period, there are ongoing costs for heating, cooling, and electricity. Our experience shows that a well-planned investment pays off quickly. The payback period for the capital investment can vary due to several factors, primarily the operating hours of the installation, the cost of the primary energy source, climatic conditions, the price of the equipment, and maintenance expenses.

Here is an example of three standard installations. The first operates without energy recovery, the second achieves 50% energy savings, and the third is a high-efficiency system with 80% energy recovery. This applies to the Sofia area, assuming the system operates 10 hours per day. If the system runs for longer periods, the advantages of high-efficiency energy savings increase. Conversely, if the system operates only a few hours per week, the high capital investment may not be recovered within the first 10 years.

There is also another interesting advantage of efficient energy-saving ventilation. The funds invested in these systems reduce the required capacity of the energy center (heating and cooling) and, consequently, the investment needed for it.

In this sense, efficient ventilation systems can effectively cost “0” leva.

Great, but besides the economic benefits, are there any other advantages of an energy-efficient ventilation system?

The advantage of reduced energy consumption through heat recovery ventilation is not just “profit.” It is clear that an investor who makes the right decision will save significant energy costs in the years ahead. It is also clear that the supplier of high-quality equipment benefits. Interestingly, the state, society, and the occupants of buildings with a good indoor climate also benefit.

Let’s imagine for a moment that thanks to effective energy savings, there is one less chimney smoking.

This leads to fewer harmful emissions, which is important for trade as well. More importantly, our children breathe cleaner air. We are taking care of the environment that we will leave to them tomorrow. We are taking care of the climate, which has already begun to punish us for our negligence over the past century.

In this context, sensible energy saving is:

• Financially beneficial;
• Healthy;
• Environmentally friendly;

Obviously, these are the ideas of the European Commission: Regulation (EU) No 1253/2014, which establishes definitive requirements.

I would like to emphasize that everything described so far is based on more than 26 years of experience of the “TANGRA” team in creating energy-efficient ventilation systems. The recuperators we manufacture, as well as the energy-recovery units and climate chambers based on them, meet the requirements of Regulation (EU) No 1253/2014, including those valid from 01.01.2018.

There are many options for implementing an energy-efficient ventilation system.

Are these standards and requirements being followed in Bulgaria? What is the behavior of investors in new buildings and of those involved in renovating old buildings? Is there any control over the efficiency of the systems?!

I am extremely pleased to note that more and more investors are recognizing the advantages of energy-efficient systems. An increasing number of designers are using systems with high-efficiency energy recovery. Buildings are also increasingly seeking certification under internationally recognized standards for energy efficiency and environmental protection, such as BREEAM or LEED. A similar approach is observed in the renovation of older buildings.

So, my answer is YES: up to now, these standards are being followed. Yes, there is increasingly more control over the efficiency of the systems. I sincerely hope that the new regulations, effective from January 1, 2016, will be correctly implemented and properly monitored.

Engineer Armyanov, we know that besides Bulgaria, TANGRA also sells its products in Europe. How is your export business developing?

Thanks to excellent quality and reasonable prices, we have clients in more than 15 European countries. We have been exporting our products for over 20 years. We have participated several times in one of the largest international trade fairs in Europe – Mostra Convegno in Italy. This year, we will take part in two specialized fairs for energy-efficient construction and low-energy buildings in the UK and Germany. I sincerely hope that we will be able to find good partners there so that we can expand our exports and demonstrate that products made in Bulgaria meet the highest standards of quality and energy efficiency.