See filen / Today the energy usage and storage is a crucial subject around the world as the need for energy is largerthan ever. In thermodynamics, three current methods exist for thermal storage: sensible heat storage,latent heat storage, and heat storage by chemical reaction. The sensible heat storage is currently themost commonly used one and involves storing heat by shifting the temperature for the storage mediumwithout causing a phase change. The latent heat storage is very much similar but with the dierencethat the medium goes through a phase change. Finally the thermochemical heat storage which diersfrom the two earlier methods by utilizing the advantage of reversible chemical processes.The purpose of this thesis is rst to establish a literature study on current studies and applications oncontrol strategy's for primarily latent heat storage, but for sensible as well. The literature study willbe composed of scientic articles and books, and a few interviews. The second part of this thesis is togenerate concept solutions for latent heat storage control strategies and a nalized design is visualizedby CAD.Based on the literature study, it can be concluded that the control technique between sensible heatstorage and latent heat storage varies because of the principles of storage. Sensible heat storage usesthe transfer uid as the material of storage which facilitate the control strategy as it is therefore only amatter of ow rate. Latent heat storage's have the transfer uid and the material of storage separatedand it requires a heat transfer process between them. Therefore, controlling the latent heat storage becomesnot only a matter of ow rate but also of contact area and conduction. On top of this, the storagematerial changes phase, which causes a reduction in power over time due to thermal resistance, andthe storage capacity will decrease because storage material for latent heat storage usually deteriorateover time. Since the storage principles dier between latent and sensible heat storage's, the establishedcontrol strategy for sensible heat storage's cannot be easily applied to latent heat storage's. Controlstrategies for latent heat storage's need to be developed, but as each challenge for latent heat storage isa dicult control-technical challenge, advanced control technology and strategy are therefore required.The result of the literature study consists of summary of all the source material to conclude the resultin matrix form and a discussion that suggested control strategy for latent heat storage is a lowdeveloped subject. The state of charge for latent heat storage is a matter that has been researchedbut has no result yet with an obvious strategy to measure the state of charge. Sensible heat storagehave control strategy solutions that could work for latent heat storage such as a general control of thelatent heat storage by a human operator or a production plan.The result on the concept creation solved a group of control strategy problems that was formulated forlatent heat storage. These are to hold constant mass ow and power, holding constant power but tobe able to adjust the mass ow, atten the power curve for the latent heat storage such that it fulllsthe requirements on power, and to calibrate the state of charge when the storage capacity has reduceddue to deterioration of the storage material. The concepts was evaluated for their pros and cons anda nal design was constructed from the best concepts. The design solves all the problems formulated,however to be something to regard as a product suggestion for a latent heat storage the design needsto solve more or all control strategy problems.
| Identifer | oai:union.ndltd.org:UPSALLA1/oai:DiVA.org:kth-276417 |
| Date | January 2020 |
| Creators | Akdemir, Gabriel, Tellgren, Sebastian |
| Publisher | KTH, Energiteknik |
| Source Sets | DiVA Archive at Upsalla University |
| Language | Swedish |
| Detected Language | English |
| Type | Student thesis, info:eu-repo/semantics/bachelorThesis, text |
| Format | application/pdf |
| Rights | info:eu-repo/semantics/openAccess |
| Relation | TRITA-ITM-EX ; 2020:221 |
Page generated in 0.0021 seconds