A leading brand in the Green Energy Solutions market looked for a reliable solution to boost the overall efficiency of their hydrogen conversion-based fuel cell CHP, which was still in the development phase. We were challenged with the limited development space and the overall “shape” of the client’s installation. We needed to figure out a customized design with unique geometry and its arrangement in the client’s installation. Additionally, in order to manage the excess heat and increase the efficiency of the system, we needed to find a solution to several factors of the device’s operation: the ability to work with three different working agents (exhaust gas, air, and hydrogen), insufficient heat transfer area, massive volume flow, high temperature differences between the working mediums, and leakage prevention.
Our engineers came up with the idea of a multipass heat exchanger. We developed a concept of a uniquely shaped tube bundle divided into two sections for hydrogen preheating and air preheating. We enclosed it in a cubic shell, thus creating a third section for cooling the hot exhaust gases. Flat, obround tubes instead of circular ones—with the new, in-house manufactured tubing solution—we managed to fit more tubes into the tube bundle and enhance heat transfer area. In order to counteract the massive flow-induced vibrations and resonation, the external surfaces (shell and manifolds) were reinforced with ribs welded to them. Additionally, the exchanger was equipped with compensation elements, welded between the shell and each edge of both tube sheets. The prevention of hydrogen leakage was achieved by minimizing the number of welds and separating hydrogen manifolds from adjacent manifolds, reducing the risk of overheating the welding connections.
We were able to increase the final heat transfer surface by nearly 20% while maintaining the limits of pressure drops for each side. We created an exchanger with a thermal profile that met all the requirements set by the client. The entire device was made of 316L SS and passivated to provide outstanding corrosion resistance and undisturbed performance in the environment of hydrogen and hot exhaust gases. Strength verification, performed by a series of FEM analyses, covered all possible operation cases and confirmed exceptional durability to work reliably under given conditions. The exchanger performance and perfect adjustment to the space constraints were exactly what the client hoped for. The client decided to continue the project and extend the product range with an additional solution: a 2-pass unit exchanger.
A client contacted us with a request – a reliable solution to boost the overall efficiency of their hydrogen conversion based fuel cell CHP. The limited space in the installation and the overall “shape” of the designed product were the real issues. We came up with an idea that the heat could be effectively used to increase the efficiency of the entire system by implementing the following processes: preheating the air that is a part of air and gas combust mixture, and preheating the hydrogen that is to be conversed in the fuel cell. We developed a concept of oblong rectangle bundle of circular tubes divided into two sections – for hydrogen preheating and air preheating. We enclosed it in a cubic shell, thus creating a third section – for cooling the hot exhaust gases. With the in-house manufactured tubing solution, we were able to put more of the tubes into the bundle, witch allowed us to increase the final heat transfer surface by nearly 20%. The exchanger was featured with compensation elements, welded between the shell and each edge of both tube sheets. To provide additional prevention against hydrogen leakages we simplified the hydrogen side to reduce the number of its components, and thus minimizing the number of welds. Hydrogen manifolds were also properly separated from adjacent manifolds, reducing the risk of overheating the welding connections. The exchanger was made of 316L SS and passivated to provide outstanding corrosion resistance and undisturbed performance in the environment of hydrogen and hot exhaust gases. The product performance and perfect adjustment to the space constraints was exactly what the client hoped for. To our further satisfaction, few months later we received a new request from the client – extension of the product range with a 2-pass unit.
