Condensing and modulating gas fired unit heater - G | Robur

It is not an easy task to find a really effective way for heating of commercial and production premises of medium or large areas; a way, which would render comfort and be economic. The heating & cooling company ROBUR with its business run all over the world, and with its long-lasting experience in the production and supply of heating equipment throughout Europe, has things to offer. The products of this Italian company demonstrate technological progress, which helps saving energy resources and brings benefit to people.

ROBUR offers the new-generation condensing and modulating gas fired unit heaters – model G – as one of the most effective ways of heating with natural or liquefied petroleum gas (LPG). These are the heaters that can achieve the efficiency of as much as 105% and reduce energy consumption by up to 25% in comparison to other heaters of this type. The tests performed by ROBUR Research and Development Center as well as the units installed all over Europe have proved that series G gas fired unit heaters are capable of warming up a medium or large area premise (a factory shop, workshop, warehouse, sports hall, health care center, indoor tennis court, bowling alley, laboratory, greenhouse, etc.) within 30 min. The modulation functions in the heater allow increasing the level of comfort. This means that the heating power can be adjusted in the range of 40% to 100%, and that the stream of the air coming from the fan can be set for operation at any of the three available speeds; e.g., the unit starts at its maximum capacity and warms up the premise within short time; later on, it reduces the power and undertakes keeping the temperature at the required (desired) level only. This allows higher efficiency, larger energy savings and more comfort to people and the environment.

Fig. 1: Temperature distribution in the pyramid-shaped heat exchanger

The key secret of the high efficiency of the air heaters from ROBUR is a special proprietary heat exchanger in aluminum alloy with ‘Ground Effect’. The thermal conductivity of aluminum alloy is higher than the thermal conductivity of steel by as many as 10 times. This renders homogeneous, evenly distributed temperature over the surface of the heat exchanger. The pyramid-shaped heat exchanger distributes an air stream to different temperature layers: higher temperature is kept at lower levels and vice versa (see Fig.1). So, therefore, colder air forces hotter air down and hinders it from going up, thereby reducing heat stratification in the atmosphere. ROBUR have proved that, with series G heaters in operation, the difference between the temperatures at the height of 1 and 6 m is 1.5 °C only: the temperature at the height of 1 m is 19 °C, meanwhile, that at the height of 6 m is 20.5 °C (see Fig. 2). The pyramid-shaped heat exchanger from ROBUR is also distinguished for the better preheating of the whole air stream produced by the fan. This is due to a special design of the heat exchanger which facilitates minimum clearances in-between heating plate-fins (see Fig. 3). The area of the surface of the heat exchanger is significantly larger than that of standard heat exchangers: in the inside, the exchanger has aluminum alloy fins arranged in a vertical circle which (fins) are passed by flue gas (combustion products), and on the outside, it has aluminum alloy plates arranged horizontally around it to render some additional area for heating of ambient air (see Fig. 4). All in all, we have a compact unit with a smaller, however, more effective heat exchanger capable of producing more heat.

Fig. 3: ROBUR heat exchanger profile

Fig. 2: Average air stratification, upon three types of gas systems compared

What is the principle of operation of series G gas fired unit heaters from ROBUR? First of all, an inlet fan turns on and the best gas-to-air ratio is mixed in a special combustion pipe (Pre-Mix). An electrode ignites the air-gas mixture; this produces a long and even flame which is burning all over the drum-shaped part of the heat exchanger (1). Then, the heated up gas (the heat from the burning process) travels upwards by warming up the special part of the pyramid-shaped heat exchanger (2). This is the main part of the heat exchanger thanks to which an air stream is divided to different temperature layers (higher temperature at the top, lower – at the bottom). Before the flue gas is exhausted, it has to pass the additional third part of the heat exchanger (3) by warming such up. An axial-flow fan evenly blows the heat off the heat exchanger over to the premise through an adjustable grille. Any condensate is collected by a steam trap (4), and the special condensate escape syphon (5) removes the accumulated liquid from the heater. Once cooled down, combustion products are exhausted through a flue duct (6).

Fig. 4: The inside of ROBUR G heater (rear view)

Series G gas fired unit heater is special because it has an additional condensing heat exchanger. Here, combustion products are cooled down to the maximum possible degree before entering the flue gas exhaust system – the flue duct / air duct. This way, maximum quantity of heat is supplied to the premise, and only a small part thereof is released with flue gas.

Unlike any of the best available on the market condensation boilers, series G gas fired unit heaters do not require a water distribution system which renders better general efficiency of the system. They do not need any central heating system either, so their installation costs are lower. Thanks to the support brackets, heaters are installed just over the floor, in the room that needs to be heated – no area of the flooring is occupied.

Series G modulating gas fired unit heater is the newest solution for effective heating of commercial and production premises. The heaters are autonomous units subject to full modulation; the amount of energy consumed by them is that required at the particular moment only. Series G gas fired unit heaters have no inertia; they will provide the required amount of heat in just half an hour and, then, will keep such at the same level only. In respect of the price and quality, ROBUR G is the best solution with minimum gas consumptions and a quick pay-off period!

The advantages of series G modulating gas fired unit heaters:

• The Italian Company ROBUR is one of the most reliable heating companies in Europe engaged in scientific researches, seeking innovations, showing its concern about employees and respecting the environment. ROBUR offers solutions which facilitate energy efficiency and help reduce the negative effect on the environment.
• Full modulation – the heating power can be set at 40% to 100%, and the speed of the fan can be adjusted at any of the 3 available levels. Using a digital chronothermostat in a premise, the heater is capable of identifying the effective indoor temperature and to duly modulate the heating power as well as the air blow to ensure comfortable temperature in the premise under any heater operation conditions.
• Heat exchangers with Ground Effect. The patented pyramid-shaped heat exchangers in aluminum alloy reduce heat (air) stratification in a premise: thanks to them, the difference between temperatures at different levels is small. The area of the surface of such heat exchanger is significantly larger than the area of standard heat exchangers which allows transmitting a larger amount of heat.
• Pre-Mix burners from stainless steel represent the new (improved) burner technology that produces a long and even flame which improves temperature distribution within a heat exchanger. The burner is controlled by an advanced microprocessor which allows the best gas-to-air ratio under any working conditions, and reduces CO and NOx emissions down to the minimum at the same time. In addition, regulation of the pre-mix allows preventing problems in the exhaust system.
• Quality guarantee – this is a European product with 100% of its manufacture done in Italy. Its technical parameters meet the declared values, as provided for in CE certificate. All the heaters from ROBUR have been certified for C type installation. This means that the combustion circuit is completely isolated, and all combustion products are exhausted to the outside. The heaters are made from premium quality components (steel casing coated in epoxy powder, axial-flow fan, burner from stainless steel, heat exchanger in aluminum alloy, drum-shaped heat exchanger from stainless steel).
• Compact, easy to install. One of the best heaters available on the market based on the power-to-weight ratio. Low installation and time costs.
• A recirculation chamber can be connected to supply fresh air.
• Extensive application: workshops, factories, warehouses, car showrooms and washes, garages, logistics centers, gyms and fitness centers, exhibition areas and conference halls, shopping malls, churches, laboratories, greenhouses, indoor tennis courts, bowling alleys and other commercial as well as industrial buildings of medium or large area.

Each condensing G Series heater is equipped with:

1. digital remote control (control, setting and diagnostic of functioning);
2. condensate drain siphon;
3. LPG kit;
4. wall template;
5. use and maintenance manual of the heater.