ROTEX GasSolarUnit: Renewable and sustainable. GasSolarUnit For heating and hot water. A strong team: Sun and gas condensing technology. Enjoy energy savings: Energy is becoming more and more precious and expensive. The most economical use of energy and the meaningful use of renewable energies with simultaneous increase in comfort, cosiness and safety is our goal. In order to meet these requirements we are looking to new product solutions and system concepts. The new GasSolarUnits by ROTEX with their integrated structure and special properties, provide the prerequisites for you to enjoy saving energy to the full: ■ ■ ■ ■ ■ Utilisation of renewable energy Constant hot water supply Optimum water hygiene Comfortable operation Weather compensated The good heating system: regenerative, economical and comfortable Dreamlike dimensions for your heating: Heating and hot water in a surface area of just 0.36 m2 The gas condensing boiler integrated in the ROTEX GasSolarUnit is a Whether with or without solar energy development which has been utilisation, the ROTEX GasSolarUnit is introduced with an optimum comthe incorporation bination of highROTEX of the latest comefficiency condenGasSolarUnit bustion and heat sing boiler and technology hygienic hot water ■ Gas condensing boiler and knowledge storage tank. hot water storage tank and base. The result is solar storage tank all in one simple structure, The uncompromi■ Energy saving with problem-free sing combination maintenance and of these functions efficiency rates of up to 110% exemplary energy permits the ■ Compact and space saving efficiency. GasSolarUnit to unit set completely ■ Optimum hot water hygiene The integration of new standards in the condensing space-saving and ■ Integrated solar energy boiler in the hot energy utilisation. utilisation (optional) water storage tank In a space of just ensures that 0.36 m2 (GSU 320) 2 surface losses are kept to a minimum. or 0.64 m (GSU 520 S/ 530 S) the Cooling losses that arise in normal complete heating system, the hot heating boiler / storage tank combiwater preparation and a solar stratified nations do not arise in this storage tank can be accommodated. application. Here again you will save energy. NEW: GasSolarUnit GSU 320 the amazing room unit Gas condensing heating boiler efficiency levels up to 110% The new design of the aluminium boiler body with a central burner chamber and its spiral additional heating surface means the ROTEX GasSolarUnit achieves an outstanding degree of efficiency of up to 110%.  We are setting completely new standards in room space utilisation and space take-up with the GSU 320. Your entire central heating system can be accommodated in a floor area of just 59 x 61 cm. Including the hot water preparation and a 280 litre solar storage tank. It really could not be more compact. Because of these ideal dimensions the GSU 320 can fit in any house or apartment. It supplies heating and hot water comfort that you soon will not want to live without. And you have the facility, at any time, to heat the storage tank with solar energy by adding a ROTEX Solaris system, thereby making massive energy savings in hot water preparation. ROTEX GasSolarUnit: More than you would expect: Everything included that you may need. All in one unit This is how it works ■ Minimum energy consumption as a result of consistent condensing technology utilisation and integration of heating boiler and hot water storage tank ■ Optimum water hygiene ■ Space saving compact layout ■ Solar energy utilisation can also be retrofitted ■ Active contribution to climate change and the greenhouse effect by sizeable reduction in CO2 emission ■ Pleasantly quiet running ■ Low cost installation by preassembly ■ Simple and cost-effective maintenance ■ Extensive state support for condensing boilers and solar energy installations ■ Weather compensated In the GasSolarUnit a gas condensing boiler is integrated in a hot water storage tank. The domestic hot water storage tank is filled with storage water which is not pressurised. The storage water is heated by the condensing boiler via a stainless steel corrugated pipe heat exchanger. Alternatively, the storage tank can also be heated using solar energy. For heating the domestic hot water there is a stainless steel corrugated pipe heat exchanger over the full depth of the water on the inside of the storage tank. The large heat exchanger surface area means that correspondingly large volumes of domestic hot water can be heated in a short time period. The storage tank is therefore always operating as a stratified storage tank. This increases the storage tank potential considerably and ensures optimum use, particularly when using solar energy utilisation. Even without the use of solar energy utilisation, the stratified storage concept permits the preparation of even larger volumes of hot water. The integrated condensing boiler has a fully-electronic digital control system. This provides weather-dependent control of the feed temperature. It controls the storage tank temperature and contains individually-adjustable time programs for the heating and for hot water preparation. GSU 320  GSU 520 S/GSU 530 S/GSU 535 In the midst, not just a spectator The compact layout means that the required floor area and installation costs are kept to a minimum. A floor area of just 59 x 61 cm (0.36m2) or 79 x 79 cm (0.64 m2) can accommodate the complete gas condensing boiler with hot water storage tank and solar storage tank. Since the unit does not need to be wall-mounted, and is entirely mounted flat on the floor, installation is child's play. Noise transmission from the unit to the building is therefore effectively prevented. Innovative down to the last detail. The heart: The gas condensing boiler The aluminium boiler body of the gas condensing boiler is a true innovation. It is flat and round and has a centrally arranged burner chamber. The flue gas is directed in a spiral around the burner chamber and then drawn away upwards. The condensate produced by cooling the flue gases is collected in the boiler body and is drained from the collector via a plastic tube. The gas burner: variable, quiet and efficient The high-efficiency surface burner fitted ensures optimum and toxic-free combustion. This burner operates in a fully modulating mode i.e. it matches its output directly to the demand. The output ranges: ■ 4 to 20 kW in the GSU 320 ■ 4 to 20 kW in the GSU 520S ■ 6.5 to 30 kW in the GSU 530S ■ 8 to 35 kW in the GSU 535 The burner operates extremely quietly. GSU 320 with Alpha 23R GSU 320 with Theta 23R It thinks for you The electronic control system 2. Theta 23R The control management of the ROTEX GasSolarUnit is performed by a fullyelectronic digital control system. There are two different versions: - Alpha 23R - Theta 23R 1. Alpha 23R The digital control system Alpha 23R has a clear four digit display which is integrated in the upper section of the ROTEX GasSolarUnit. All the fundamental functions are selected using two rotary switches. The values can be adjusted simply using push-buttons. The Alpha 23R has three time programs for the control of the heating circuit and the hot water preparation. The time controls are preprogrammed; one of these can be adapted to the individual wishes of the user. In addition, the Alpha control system is prepared for controlling an additional mixed circuit. The heating water temperature is automatically adjusted according to outside temperature. The control system itself senses winter and summer and switches the heating system on or off as required. The fully-electronic digital control system Theta 23R meets the highest of demands. The display shows values and parameters in clear text. The main operating element is a selector knob with which the operating modes, time programs and operating parameters can be set and quickly and simply altered. Fundamental system parameters can be viewed and adapted by the heating engineer. The heating water temperature is automatically adjusted according to outside temperature. The control system itself senses winter and summer and switches on or off the heating system as required. The Theta 23R has individually adaptable time programs for simple control of the heating circuit and hot water preparation. It can also be used to control an additional mixed heating circuit. This requires that only the mixer, pump and sensor are plugged into the control housing. It is also possible to connect an additional circulation pump. The Theta 23R control system can be extended by room controllers and thermostats which conveniently control and monitor the heating system.  Air in – flue gas out The heat stays inside The GasSolarUnit is operated in room air independent mode as standard. The burner draws the necessary combustion air directly from the outside through an installation shaft or a double-walled flue gas duct. The storage tank is a twin layer structure made entirely from plastic. The space between the internal and external tank is filled with expanded foam and is extremely heat insulating. This high level of insulation ensures low overall heat losses for the ROTEX GasSolarUnit. Advantages of room air independent mode: ■ The boiler room does not need a ventilation opening to the outside and thus does not get cold ■ Lower energy consumption. ■ Dust, solvents, detergents etc. are not drawn in by the burner. This means that the room can also be used as a laundry, workshop or similar application ■ Also possible in roof space siting ■ Additional energy savings due to the flue pipe preheating the combustion air Hot water, as much as you want – as often as you want The domestic hot water is contained in a stainless steel corrugated pipe which extends in a spiral from bottom to top of the storage tank which is filled with unpressurised water. The fresh water which is drawn in is heated in the flow principle. This type of water direction creates stable, clearly defined temperature stratification. Corrosion resistance, low tendency to calcification and, above all, optimum water hygiene characterise this type of heating. The large storage tank capacity ensures that the SolarUnit always provides sufficient hot water. This provides the highest levels of water comfort. And when you heat the GasSolarUnit with solar energy, hot water is available practically cost-free throughout the summer – you can then "enjoy saving energy". Water hygiene is our principle The structure of the ROTEX GasSolarUnit ensures that it has optimum inherent water-hygienic properties since the water to be heated is directed and heated through a piped system. The water volume in the domestic hot water heat exchanger is just 19/24 litres, and thus amounts to only a fraction of the volume of water in normal storage tanks. Low flow sections or sections that are not heated properly on the hot water side are completely eliminated using the ROTEX GasSolarUnit. The domestic hot water is entirely contained in a piping system so that the deposits such as sediment, rust or other deposits which can arise in large volume tanks are not produced. Water that is charged first is also the first to be removed (first in first out principle). The outstanding hygienic advantages of this type of hot water storage tank have been confirmed in extensive tests performed at the Institute of Hygiene at the University of Tübingen. Keyword: Legionella  Legionella bacteria There are about 35 types of Legionella. At least 17 of these produce illness. The main consequences are: Pontiac fever: flu-like symptoms which subside after a few days. Legionnaire's disease: severe bacterial lung infection. In 15 to 20 percent of the cases the infection leads to death. ROTEX GasSolarUnit EnEV values to dream of. The EnergySavingDirective (EnEV) has been in force since 01. 02. 2002. A new feature is that the EnEV not only limits the heat demand of the building, but also takes into account and evaluates the entire heating system. The ROTEX GasSolarUnits maintain the values stipulated by the EnEV in an optimum manner, and exceed them clearly by virtue of the following properties: ■ Condensing technology utilisation ■ Ambient air-independent mode (LAS) ■ Lowest possible standing losses in the heating boiler ■ Low consumption figure in domestic water preparation ■ Solar energy utilisation for domestic water heating ■ Solar heating support for LTHW Heating on GSU 520 S and GSU 530 S ■ Low surface losses from the storage tank 100 % 100 % Relative energy costs The heating energy demand for new buildings is now around 30% less than the requirements of the previous heat insulation directive. Anyone who is building a house at the moment must ensure that his house falls within these threshold values. In addition to a retentive building casing, an optimised heating system plays an important role. Relative total energy costs as a function of the installation consumption figure ep 90 % 80 % 82 % 70 % 68 % 60 % 50 % 51 % 45 % Low temperature heating boiler, heating radiators 55/45 °C and floor heating 35/28 °C (two separate circuits, two circulation pumps) eP = 1,88 Condensing heating boiler, heating radiators 55/45 °C and floor heating 35/28 °C (two separate circuits, two circulation pumps) eP = 1,54 Energy cost savings The energy consumption of a heating system is directly dependent upon the installation consumption figure ep. Thus, the energy costs of an installation are directly proportional to the installation consumption figure ep. In the example quoted it becomes clear to what extent you can save energy costs using the installation technology. You can thus reduce the ongoing energy consumption costs when Condensing heating boiler, ROTEX System 70 floor heating and heating radiators 55/45 °C (one common heating circuit, just one circulation pump) eP = 1,28 Condensing heating boiler, ROTEX System 70 floor heating and heating radiators 55/45 °C (one common heating circuit, just one circulation pump) and solar energy utilisation for hot water and heating eP = 0,96 heating with a condensing boiler and solar energy incorporation to 51% of that required by normal heating using a low temperature boiler. The initial parameters for the three installations on the right are the same: Condensing boiler with room air independent operating mode, installation in a balanced flue, internal distribution, domestic water utilisation without secondary hot water circulation. Building effective area AN = 150 m2 A/V ratio: A/N = 0,75 m-1 Specific heat demand: 59 kWh/m2a  Integrated solar energy utilisation for heating and hot water. As much sun as possible – just enough gas to meet the need. The ROTEX GasSolarUnit (GSU 520 S/ GSU 530 S) not only uses the power of the sun for domestic hot water heating but also for supporting the heating system effectively. If you decide not to incorporate a solar installation at this time, the solar support system ROTEX GasSolarUnit can easily be retrofitted. If the sunshine is insufficient, or if the GasSolarUnit does not need any more heat, the feed pump switches off and the entire Solar System drains into the storage tank. The addition of antifreeze is not necessary because if the installation is not in use, the collector surfaces are not filled with water - another environmental advantage! Solar heating support A heat exchanger composed of a stainless steel corrugated pipe is connected to the bottom of the boiler Use the cost-free energy of body for solar heating support. This the sun without being diverheat exchanger projects into the buffer ted area of the tank filled with unpressurised water. All the boiler The solar connectors ROTEX Solaris water flows through it continuously. are used for solar energy utilisation. In The heat exchanger is surrounded by a addition you will need a control and heat insulation pump unit and a casing which is connection set. R O T E X G a s S o l a r U n i t open at the This involves bottom and which removing the therefore, is in storage water for ■ Gas condensing boiler and heat exchange the ROTEX Gassolar storage tank all in one mode with the SolarUnit from the lowest and coldest ■ Energy saving with efficiency solar zone of the levels up to 110 % storage tank. If the point of the temperatures are storage tank and ■ Compact and space-saving above the heating then feeding it unit return temperature directly, i.e. ■ Optimum water hygiene in the solar zone, without using a heat exchanger, to the solar collectors. The water is heated here and then stratified back into the GasSolarUnit. This considerably increases the efficiency of the solar collectors and the entire utilisation of the installation. The entire Solaris System works at atmospheric pressure.  thermal circulation is created in the heat insulation sleeve. This leads to solar increase in the return temperature. In the transition period in particular, the heating can be effectively supported by the sun. ROTEX GasSolarUnit: Solar energy for hot water and heating! Economical and effective Since the system is unpressurised, the components that would otherwise be required, such as an expansion vessel, pressure relief valve and heat exchanger, are not required. This not only saves money when purchasing the installation, but also increases security of operation. Good for the environment The GasSolarUnit is in all aspects beneficial for the environment: ■ Lowest possible environmental loading as a result of the most up-to-date technology ■ Reduction in CO2 emission by: - modulating condensing technology - consistent solar energy utilisation ■ Absolutely glycol-free solar circuit GSU 520 S, 530 S A B C D E F G Gas condensing boiler Hot water stratified storage tank Unpressurized storage tank water Active water zone Solar zone Heating support zone Control and pump unit (Accessories) 1 2 3 4 5 6 7 Domestic water heating applications Solaris connection Flue gas Air supply Condensate drain Domestic hot water heat exchanger (stainless steel) GasSolarUnit (GSU 520 S/ 530 S) – Structure and function The boiler body of the condensing boiler is integrated in the upper section of the storage tank. The storage tank in the GSU 520 S/ GSU 530 S is split into two function zones: into the active water zone (D) at the top, and the solar zone (E) at the bottom. 8 Storage tank charging heat exchanger (stainless steel) 9 Solar heating support heat exchanger (stainless steel) 10 Heating heat exchanger 11 Heat insulation sleeve 12 Fan burner 13 Non return valves (accessories) The domestic water heat exchanger, made of stainless steel corrugated pipe, extends over the entire depth of the storage tank. The fresh water is fed in at the lowest point of the storage tank. From here it is directed upwards in the stainless steel corrugated pipe which acts as a heat exchanger, in a spiral manner. It is continuously heated as it passes through the storage tank. This arrangement produces defined temperature statification with the hot water preparation. This stable temperature stratification is a significant prerequisite for highly effective utilisation of solar energy. This always removes the coldest water in the storage tank from the lowest point of the tank, transports it to the solar collectors on the roof and then feeds it back into the storage tank via a special stratifying charging system. This permits optimum energy exploitation in solar energy utilisation.  The energy bundle for heating and hot water with solar option. GSU 320 – Highest possible hot water comfort GSU 535 – Hot water with no boundaries The GSU 320 offers the maximum output in the smallest space. It uses the total tank volume of approx. 280 l for heat storage and can thus accommodate high demands for hot water without any problems. The GSU 535 is the ideal solution for installations for high levels of heat and hot water demand. Here again solar energy utilisation can be used for the preparation of hot water. The GSU 320 is fitted with all the connections required for solar heating. Especially with the system for ensuring optimum temperature stratification in the storage tank. [ 10 ] Several units can be combined together for this application. This adds the resulting heat output for heating and for hot water output. In this way, a system comprising several GSU 535 units can be the economical, efficient and waterhygienic perfect solution for hotels, old peoples homes, hospitals, sports halls or similar applications. GSU 320 A B C D E GSU 535 Gas condensing boiler Hot water stratified storage tank Pressure-free storage tank water Active water zone Control and pump unit (accessories) 1 Domestic hot water 2 heating applications 3 Solaris connection 4 5 6 7 8 9 10 11 Flue gas Air supply Condensate drain Domestic hot water heat exchanger (stainless steel) Storage tank charging heat exchanger (stainless steel) Heating heat exchanger Fan burner Non return valves (accessories) GasSolarUnit (GSU 320/ GSU 535) – Structure and function The entire storage tank is used as a hot water storage tank. Thus, the charging heat exchanger, made of stainless steel corrugated pipe like the domestic hot water heat exchanger extends over the full depth of the storage tank. A B C D E Gas condensing boiler Hot water stratified storage tank Pressure-free storage tank water Active water zone Control and pump unit (accessories) 1 Domestic hot water 2 Heating applications 3 Solaris connection This means that the total heat capacity of 500 litres of storage tank water is available for hot water preparation, the hot water output is thus at a maximum. When hot water is drawn off, using the GSU 320 and GSU 535, a distinct temperature stratification is produced, and this maximises the volume of hot water that can be removed. 4 5 6 7 8 9 10 11 Flue gas Air supply Condensate drain Domestic hot water heat exchanger (stainless steel) Storage tank charging heat exchanger (stainless steel) Heating heat exchanger Fan burner Non return valves (accessories) The large charging power rating of up to 20 or 35 kW and the rapid reaction time in heating up because of the boiler not cooling down mean that the hot water preparation and hot water comfort of the GasSolarUnit are very high. [ 11 ] [ 12 ] Flow diagram for GSU 320, GSU 520 S, GSU 530 S, GSU 535 Pressure drop in mbar Flow rate in l/min Flow rate in l/hour a) Drinking water heat exchanger (38 m) GSU 520 S/GSU 530 S/GSU 535 b) Drinking water heat exchanger (28 m) GSU 320 Storage tank temperature 60 °C draw-off temperature 40 °C cold water temperature 10 °C Promotional programs Draw-off rate in l/min Draw-off diagram for GSU 320, GSU 520 S, GSU 530 S, GSU 535 max. draw-off volume in litres The Federal Department of the Economy (BAFA) promotes new construction and renovation of heating installations in combination with solar energy utilisation. In addition there is a wide range of promotion programs in the various Federal States. Information from e.g.: www.carbontrust.co.uk, www.lowcarbonbuildings.co.uk, www.eca.gov.uk, www.rotex.de Maximum 12 m Energy saving and utilisation of solar energy are in the interests of everyone. For this reason your commitment to the environment is promoted by a large number of programs: [ 13 ] Technical data GasSolarUnit Basic data Total storage capacity Litres Empty weight kg Total filled weight kg Dimensions (L x B x H) cm Max. permissible storage tank water temperature °C Readiness heat consumption at 60 °C kWh/24 h Drinking water heating Drinking water capacity Litres Maximum operating pressure bar Drinking water heat exchanger material Drinking water heat exchanger surface m2 Average specific heat capacity W/K Storage tank charging heat exchanger Water capacity heat exchanger Litres Surface area charging heat exchanger m2 Average specific heat capacity W/K Solar heating support Heat exchanger surface area m2 Average specific heat capacity W/K Thermal output data Output characteristic value NL according to DIN 4708 1) D value (specific water flow to EN 625 2) l/min Continuous output according to DIN 4708 Qn kW Max. draw-off rate for a period of 10 min at (TKW = 10 °C/TSP = 60 °C/TWW = 40 °C) l/min Hot water quantity without reheating up to 15 l/min tapping rate (TKW = 10 °C/TWW = 40 °C/TSP = 60 °C) Liter Hot water volume with heating up at nominal output and 15 l/min draw-off rate (TKW = 10 °C/TWW = 40 °C/TSP = 60 °C) Litres Short-term water quantity in 10 min Litres Heat generator characteristic data Nominal output kW Rated thermal load kW Device type Product ID number NOX class Electrical data V/Hz Electrical power consumption (including heating circulation pump) W Protection rating IP Maximum permissible operating pressure bar Maximum permitted operating temperature °C Maximum boiler efficiency % Flue gas / air infeed connection diameter mm Pipe connections Cold and hot water Inch Heating inflow and return flow Inch GSU 320 GSU 520 S GSU 530 S GSU 535 300 86 386 59.5 x 61.5 x 189 85 1.7 500 124 624 79 x 79 x 181 85 1.8 500 128 628 79 x 79 x 181 85 1.8 500 128 628 79 x 79 x 181 85 1.8 19 10 stainless steel 4.1 1820 24.5 10 stainless steel 5.5 2 470 24.5 10 stainless steel 5.5 2 470 24.5 10 stainless steel 5.5 2 470 10 2.1 910 10.4 2.3 1040 10.4 2.3 1040 19.5 4.3 1950 - 0.43 200 0.43 200 – – 2.0 23 20 2.1 25 20 2.2 27 30 4.4 39 35 20 21 22 31 200 220 220 412 360 200 500 210 1180 215 unbegrenzt 310 4.0-20.1 4.1-21.0 4.0-20.0 6.5-30.0 4.1-21.0 6.6-30.9 / C 33x / C 43x / C 53x / C 63x / C 83x CE-0085 BM 0065 5 5 230/50 230/50 8.0-35.0 8.5-36.1 max. 114 20 3.0 85 110 80/125 max. 114 20 3.0 85 110 80/125 max. 127 20 3.0 85 110 80/125 max. 159 20 3.0 85 110 80/125 1” AG 1” IG 1” AG 1” IG 1” AG 1” IG 1” AG 1” IG B 23 5 230/50 5 230/50 At nominal output, 80 °C feed temperature, 65 °C storage tank temperature, 45 °C hot water temperature and 10 °C cold water temperature Explanation: The specific water flow to EN 825 is the flow of drinking water at an average temperature increase of 30 K that the GasSolarUnit can supply during two consecutive draw-offs of 10 minutes each, starting from a charging temperature of 65 °C. The standard calls for a delay between the draw-offs of 20 minutes. The GasSolarUnit achieves this value even at shorter delay periods. 1) 2) [ 14 ] Solaris flat collectors V 21 A V 26 A H 26 A Dimensions L x B x H Net surface area Aperture surface area Absorbing surface area Weight Water content Absorber 2000 x 1006 x 95 mm 2000 x 1300 x 95 mm 1300 x 2000 x 95 mm 2.60 m2 2.60 m2 2.01 m2 1.80 m2 2.35 m2 2.35 m2 2 2 1.78 m 2.33 m 2.33 m2 40 kg 50 kg 50 kg 1.6 Liter 2.0 Liter 2.2 Liter harp-shaped copper pipe register with laser-welded highly selective coated aluminium plate Coating Glazing Heat insulation Max. standstill temperature Sunselect, Absorption approx. 97 %, Emission approx. 4 % Single pane safety glass, Transmission approx. 92 % Rock wool (collector base 50 mm, side components 20 mm) approx. 200 °C The collectors are standstill resistant over a long period and are tested for thermal shock. Minimum collector yield over 525 kWh/m2 at 40 % covering proportion, Location Würzburg Control and pump unit RPS 3 Dimensions W x D x H Operating voltage Max. electrical power consumption Control 230 x 142 x 815 mm 230 V/50 Hz 20-90 W (modulating*) digital differential temperature controller with clear text display Pt 1000 PTC FLS Collector sensor Storage tank and return sensor Feed temperature and flow sensor (accessories) * modulating operation mode only possible with FLS [ 15 ] Cosy heating and hygienic hot water make a house a home. Energy is becoming more and more precious and expensive. An energy saving heating system can increase personal comfort and save energy at the same time. You are therefore investing in the future today. The potential for energy saving in heating systems is enormous and has an effect for decades. ROTEX, the heating system of the future, incorporates energy components which are perfectly matched to each other. ■ Condensing boilers for oil and gas ■ Hygienic high-efficiency hot water storage tank ■ Pressure-free and environmentally friendly solar installations ■ Floor heating and radiators using just one water distribution system ■ Odour-blocked safety storage tank ■ An interconnecting plastic installation system for sanitary and heating applications Further information can be obtained from www.rotex.de ROTEX Heating Systems GmbH Langwiesenstraße 10 · D-74363 Güglingen Fon +49 (71 35) 103-0 · Fax +49 (71 35) 103-200 e - m a i l i n f o @ r o t e x . d e · w w w. r o t e x . d e 008.1512444 · Errors and technical modifications reserved · 05/2007 Enjoy energy savings: ROTEX - The heating system with a future.