Modulär Elbilsvärmare

Sammanfattning: ABSTRACT   This thesis work consists of a case study of a fluid heater, containing both qualitative and quantitative elements. The project was carried out at Calix, a company working with different heating solutions for vehicles. The projects purpose was to investigate if a modular fluid heater could replace Calix´s current heaters for electric- and hybrid vehicles and to find out which modular factors that affect the heater function. New environmental requirements have made electrical vehicles more common. With less excessive heat and new batteries that are more sensible for low temperature, this kind of vehicles demands more powerful heaters than before. Electrical vehicles of different size, voltage and other various attributes require a new type of heater, suitable for a modular design. A pilot study has already been conducted by Calix and the project started with a preliminary project specification. Two research questions were created to answer Calix requests: RQ1 How could a modular heater be designed to enable customer adoption without time-consuming development processes? and RQ2 Which factors in the modular approach have the main impact on the heaters function? RQ1 were answered by a literature review and a product development process. Throughout different selections, with the presence of experienced personnel, the project resulted in a final concept. Different modular configurations allowed all current heaters to be replaced by the new concept. The main body of the modular heater is suggested to be manufactured by aluminium extrusion, a manufacturing process that makes it possible to integrate details directly in the profile without any extra processing. Components around the heater are designed to fit every configuration. The new concept has a lot of advantages compared to current heaters. 7 % fewer parts and more standardised components are used in the modular heater. Sealing is achieved by different O-rings and the hose connectors are replaceable due to locking rings. A new method of arranging the element tubes for low voltage heaters allows the volume to decrease by half compared to a current 28,5 V heater. The digital concept was realised as a functional prototype corresponding to a 28,5 V heater. RQ2 was answered through laboratory testing of the prototype and flow simulation of the digital concept, several factors were identified that affect the heater function. One notable factor was the inner geometry of the hose connectors, small changes resulted in a 50 % reduction in pressure drop. How the inlet was placed in proportion to the element tubes were also a big factor and was affecting the flow, temperature exchange and pressure drop. Parameters that affect less include the size of the flow, the relative location of the hose connectors and the geometry of the element tubes. The laboratory tests were conducted with two different heater effects and in different ambient temperatures, by comparing data simulations and real tests, some differences could be identified. The most significant differences were that the computer simulations did not replicate the flow increase that occurred due to the heat output and that the ambient temperature had less impact than in reality. The functional prototype test clarified that all of the components and sealings developed operated as planned, in both hot and cold conditions and that the new placement method for element tubes did not lead to any complications. The remaining work is to conduct further prototype testing, adjust the cross-section of the heaters extruded body after suggestions from two suppliers. Components around the heater should be prepared for large-scale production and it is recommended to perform a vibration and environment test on the assembly.