The European Parliament and the Council of Europe clearly defined the goals of the “Europe 2020” project – 20% fewer carbon emissions, a 20% share of renewable energy sources, and 20% higher energy efficiency. To achieve these results, Directive 2009/125/EC was introduced in the EU countries. It set out the framework for energy-related products and the requirements for their improvement (European Ecodesign Directive). The regulatory framework establishes the minimum requirements for all household and industrial products, and regulations for different types of products were introduced under the directive. Regarding ventilation and air conditioning systems, the regulatory framework was divided into two:
- ЕС 1254/2014 – energy performance and labeling of residential ventilation systems;
- ЕС 1253/2014 – energy performance and characteristics of ventilation systems intended for non-residential use;
The two regulatory frameworks set different minimum parameters for ventilation and air-conditioning equipment. The EU regulatory requirements under 1253/2014 are as follows:
- Minimum efficiency of heat exchangers (heat recovery units) for non-residential applications:
– from 01.01.2016, not less than 67% (EN 308)
– from 01.01.2018г., not less than 73 % (EN 308) Currently, Bulgarian regulations require an efficiency of no less than 70%. - Mandatory smooth control of fan speed, either through variable speed control or using a frequency converter (inverter). This applies to both the supply air fans and the exhaust air fans. Additionally, the specific fan power (SFP) is a factor that influences the energy class of the equipment.
- Bypass – the mandatory installation of a bypass damper in ventilation systems, which allows the use of outdoor fresh air as “free cooling/heating” when it is economically advantageous to do so.
The company “TANGRA” fully supports these initiatives, which have been an integral part of its development of highly efficient energy-saving ventilation and air conditioning systems since 2011. In 2012, the company introduced high-efficiency heat exchangers and energy recovery ventilation units, and since 2013, it has been manufacturing air handling units with two-stage energy recovery, achieving maximum efficiency of up to 94%.
As part of its ongoing program to develop energy-efficient systems in the fields of ventilation, air conditioning, and heating technology, the “TANGRA” team continuously improves its products and tests the results in an aerodynamic laboratory.
At the beginning of 2017, the company “TANGRA – AV” Ltd. conducted, together with the Technical University of Sofia and under the supervision of Prof. Dr. Eng. Ivaylo Banov, a series of laboratory tests on high-efficiency ventilation systems and heat exchangers. The tests were based on the BDS/EN 308 standard. This testing of air-to-air heat exchangers also represents another step towards certification by EUROVENT. After initial tests confirmed the absence of leakage, uncontrolled airflow loss, or mixing of air streams, the focus shifted to determining the thermal and aerodynamic characteristics (efficiency and resistance). The results showed a minimum efficiency of 79% and a maximum of 85% under dry conditions and in compliance with EN 308. In this regard, the heat exchangers produced by the company meet and even exceed the minimum efficiency requirement of 73% effective from 01.01.2018.
It is extremely important here to explain what this efficiency means and to approach the issue professionally and honestly. When the cold outside air enters the heat exchanger (recuperator) during winter, it begins to warm up. This happens at the expense of energy taken from the expelled polluted air.
Very often, commercial materials show the efficiency of plate heat exchangers as 90% or higher. These are marketing tricks, but such efficiency can only be achieved under specific conditions, such as very humid air in the room, leading to condensation in the recuperator, and certain airflow conditions. The idea to impress the potential client is clear. In this regard, the standard for proving technical characteristics explicitly defines the rules (EN 308; DIN EN 13053).
Confident in the obtained results, the “TANGRA” team introduced into regular production the new series of energy-saving units EVB TOP, suitable for installation in technical rooms and attic spaces. Thus, the range of energy-saving ventilation equipment was expanded with one more new member:
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High-efficiency energy recovery units TANGRA EVB __ HiE :
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Compact energy recovery units TANGRA ECO __ HiE :
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High-efficiency energy recovery units TANGRA EVB __ TOP :
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Energy recovery air handling units TANGRA AHU __ ROT :
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Air handling units with two-stage energy recovery TANGRA AHU __ DEX :
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Hygienic air handling units
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Of course, the Council of Europe presents various measures not only for products but also for buildings within the EU. Below is a sample table of legal requirements:
| Building stock | Products | ||
| Mandatory | Recommended | Mandatory | Recommended |
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*Energy Performance of Building Directive (Building inventory with characteristics of the buildings) *Directive for the recovery of waste heat in public buildings (27/2012/ЕС) |
Certificates for energy performance of buildings, such as: *BREAM |
*Ecodesign – ErP, *CE – declarations |
*TUV *AMCA *Eurovent *GOST-R *Други |
The additional voluntary certification of new buildings, which is becoming increasingly common in Bulgaria, leads to the selection of higher-quality and more sustainable materials during the construction process. This not only improves the quality of life for future occupants but also ensures lower operating costs and a better commercial appeal of the building. To facilitate an easier certification process, every investor seeks products that possess not only the mandatory certificates but also some of the voluntary product certifications.
The products of the company “TANGRA” are mandatorily accompanied by a Declaration of Conformity (CE Declaration of Conformity) and an Ecodesign ErP label for the applicable products. In 2013, the company’s team certified the range of TANGRA AHU air handling units in cooperation with the German certification organization TÜV Rheinland. “TANGRA” is the first certified Bulgarian manufacturer of ventilation and air handling units.
This advantage has enabled the company to successfully complete many projects with elevated requirements in recent years:
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Today, the energy recovery ventilation and air conditioning systems from “TANGRA” are offered in more than 15 European countries, and since 2016 the company has had a distributor in Dubai, UAE.
