At the end of 2014 the company “TANGRA” completed ventilation and air conditioning systems in the factory for production of Light Emitting Diode (LED) lighting and electronic circuits printed boards of the company “Intelligent Systems of Security” Ltd.

The main goal of the site was the reconstruction, renovation and sanitation of an existing four-storey building of the Dairy industry in the town of Vratsa into a factory for manufacturing of PCB (Printed Circuit Boards) and Light Emitting Diode (LED) lighting. Company “TANGRA” has been included in the performance of HVAC (Heating, Ventilation and Air Conditioning) systems and in the improving energy efficiency of the enterprise.

The activities were carried out and financed through the Program “Energy Efficiency and Green Economy” under the Operational Program “Development of the Competitiveness of the Bulgarian Economy 2007-2013”.

New production facilities are developed on 6 500 m2. Mechanical assembly, hand and machine production are developed and located in the renovated halls.

Specific in the design and implementation of installations was compliance with technological processes (sectors with discharges of heat, odors and harmfulness). These factors led to the following solutions concerning the ventilation, heating and air-conditioning systems:

Energy center with capacity for heating and cooling 350 kW (energy recovery is recognized):

Heat pump system consisting of two types of aggregates of high-performance providing the necessary power for heating in winter, cooling in summer and preparation of heat and cold bearers for the Air Handling Units for ventilating the facility.

Water cooled heat pump Hitachi RCUE, with cooling capacity 134 kW, draws energy from a geothermal coil. Thanks to the system of multistage double screw-compressor Hitachi RCUE allow working on partial power in the transitional seasons and high efficiency.Geothermal coil in the project is circle built of pipe REHAU RAUGEO collect in the ground. This is the latest generation of high-performance diffuse collectors of REHAU for the implementation of geothermal systems.

The second heat pump is air cooled Hitachi RHUE, with a heating/cooling capacity of 246 kW, providing extra energy.Twin scroll compressors allow a smooth change of power following site requirements. This leads to increased energy efficiency.

The heating of production and administrative premises designed and constructed to be essentially accomplished by heat pumps Hitachi. In case of shortage of heating capacity during extreme winter conditions two high efficient condensing gas boilers De Dietrich, each with an output of 140 kW are installed.

Maintaining the required temperature is performed by fan coils for ceiling mounted “cassette” and for floor installation. Convectors are manufactured by Tonon Forty – Italy and have a 3 + 3 fan speeds, allowing to leave them in standby during the night and very rapid warming at the morning when employees arrive at work.

Proper ventilation (supply of fresh air for people and technological needs) is provided by zone and floor designed air conditioning and ventilation systems. Proper ventilation (supply of fresh air for people and technological needs) is provided by zone and floor designed air conditioning and ventilation systems. Four air handling units with energy and heat recovery TANGRA AHU REC ROT are installed. The first three air handling units with rotor wheel heat exchanger process 24 000m3 / h fresh air and are responsible for the production premises:

• Section “Mechanical Production”;
• Section “Manual production”;
• “Mechanical” Section.

Administrative areas are served by separate air handling unit TANGRA AHU REC 06, which delivers 5 500 m³ / h fresh air for occupants.

Installations built in the factory are connected to a centralized management system and BMS with touch-screen display. The temperature is regulated through zoning and floor temperature sensors according to the need of the inhabitants and technology. The fresh air is regulated by sensors for air quality (CO2, VOC). In addition to touch-screen display, the system can be managed remotely by computer (PC) or through the Internet.

Advantages:

All air handling units TANGRA AHU REC are constructed in such a way to ensure filtering, heating or cooling of the supply air. The built-in rotary regenerative heat exchanger recovers 68 ÷ 75 % of the energy of the exhaust air, which reduces the use of primary energy.
Only about 15 % of discarded contaminated air is unsuitable for recovery of energy, due to dangerous mixes (technological equipment). Two explosion-proof fan with outsourcing motors, S&P CRMT suck this air.

Another advantage of the implemented systems is the possibility, at the one and the same time, some systems to operate on the heating and the other on the cooling, depending on the technological needs in the different zones. This is achieved by two separate buffer vessel, each with a capacity of 3000 l., as well as four pipe heating/cooling sections in the air handling units.

Water-cooled heat pump Hitachi is independent of external conditions, allowing all year-round operation at low operating costs.

Circulation pumps in the system are Grundfos Magna 3 (latest generation of electronic pumps), enabling accurate and precise adjustment of flow, pressure and optimal performance of the system.

There is possibility of including well water in the existing system.

Energy Efficiency:
Production plant for Printed Circuit Boards and LED lighting is a good example of energy-efficient solution in ventilation, heating and air conditioning systems. It demonstrates the innovative thinking of the owners “Intelligent Security Systems” Ltd., best technical solutions and high efficiency equipment provided by “TANGRA”.

The energy required to maintain the microclimate (heating, cooling and fresh air) largely comes at the expense of energy derived from discarded air, environment and geothermal energy.

Energy savings thanks to innovative solutions is estimated at 350 MW/h per year, which does not include the effect of improved insulation. Besides financial result for the enterprise now, this brings and environmental benefits (reduction of harmful emissions and carbon footprint).