The high efficiency HRWB-2 boiler with a unique through-flow system /straight flow system.
The HRWB boiler produced by Van Dijk heating is based on the latest insights on and developments in relation to the high efficiency fire tube boiler. This boiler complies with all of the various strict environmental requirements and can be produced individually or as a small production run. This process involves the use of the materials customary in this respect and automated production techniques.
The boiler is a gas-fuelled hot-water boiler that operates at a maximum temperature of 110⁰C and a service pressure of 2 bar. The construction of this high efficiency boiler is optimal for the combustion of gas in line with strict environmental requirements. Lengthwise, the boiler features an ample furnace and a fire tube heat exchanger, which consists of a limited number of tubes with a large diameter. The special retarders supplied by Van Dijk heating have been fitted in the tubes for optimal heat transfer.
By using special retarders, the boiler achieves an efficiency of at least 86% (Hb). These retarders make it possible to attain this efficiency with large flame tubes, because of which the number of flame tubes can be kept to a minimum.
The boiler design is not suitable for condensing flue gases. It will only be possible to exchange sensible heat. To be able to utilise the latent (condensation) heat, it is possible to install a Van Dijk heating flue gas condenser behind the hot-water boiler.
To achieve the longest possible working life, it is important that the thermal stresses in the construction of the boiler are minimal. To achieve this, a great deal of thought has been given to how the water flows through the boiler. It is important that the water flows properly throughout the boiler and that surfaces with a high heat load are cooled properly, even in the event of a minimum water flow. Because of this, the boiler features various water baffles. Amongst other things, these ensure that the water on the inlet side is distributed properly vertically and also flows through the tube package evenly. The water baffles also ensure the even flow of water to and the effective cooling of the tube plate on the furnace side and for even water distribution around the entire furnace.
Advanced and intelligent controls guarantee the long working life of the boiler. Controls must ensure that no major temperature differences arise in the boiler, so that the thermal stresses in the boiler construction are kept to a minimum. The HRWB-2 boiler can be controlled effectively with the customary boiler control systems provided by the well-known horticultural computer brands. However, a number of conditions must be met. For example: briefly continuing to run the pump when stopping the burner, a minimum return water temperature of 67 °C and a minimum water flow of 30% of the maximum pump setting
All of the connections in the boiler are welded, resulting in a very strong construction with a long working life. All of the materials used are accompanied by the 3.1.B certificate and have been produced in line with EN 10204.
The design calculation and construction have been effected in line with the rules for pressure vessels, also referred to as the ‘Stoomwezen rules’. The CE quality mark laid down in the European Pressure Equipment Directive, PED module B has been granted. An application has been submitted for the CE quality mark, which requires compliance with the requirements set out in the Gas Appliances Directive (90/396/EEC).