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This investigation was done as part of the ISECOP project (Energiforskning grand number: 64017-05102), where a heat pump was used for heating and cooling two storage tanks simultaneously, as it is presented in Figure 1. The part of the system investigated using Computational fluid Dynamics (CFD) is the one marked with a red square in Figure 1. In order to make the modelling easier, the hot and the cold side of the heat pump were individually simulated, following the same methodology presented below. The objective of this project was to examine the effect of the tank design on the COP of the tank-heat pump system during charge and discharge. Parameters such as the tank geometry, flow rate, diffuser plate geometry and tank material were investigated using CFD, in order to determine the effect of these parameters on the final performance of the system.

NoBriner (www.nobriner.org) aims to develop a technology to manage brine, a byproduct from the desalination process when producing safe drinking water from saline water sources. As a solution, a zero-liquid discharge desalination method, based on spray evaporation, is targeted - as a stand-alone solution, which can be combined with various desalination processes and heat sources. Furthermore, for application in rural areas with poor access to infrastructure, the technology is required to be low maintenance. Literature study was performed on characteristics of different desalination processes, with a focus on reference solutions for zero liquid discharge of brine as well as on system aspects in relation to the aimed NoBriner spray evaporation solution. Brine characteristics were determined experimentally (sample from Kenya) and by database screening. Investigations on sustainable implementation focused on social aspects and available infrastructure, dependent on the location. Furthermore, reference solutions for brine utilization were studied. The potential market was explored for brine as a multifunctional product. NoBriner worked on business development regarding the outlook of potential clients and projects. Zero-liquid discharge of brine was theoretically investigated by means of detailed models for droplet evaporation of pure water and brine. Literature findings were utilized to build and a standalone simulation program in Python. It was possible to verify the droplet evaporation model for pure water, which was utilized for experimental spray evaporation setup dimensioning. Thus, when brine is experimentally tested, the model can be updated in the future. To facilitate a future experimental validation of the zero-liquid discharge concept, DTU Byg planned an experimental spray evaporation setup. Components were selected and sized - at this stage the setup could be realized at DTU Byg after the necessary material (pipes, fittings, spraying equipment) is purchased.Furthermore, NoBriner and DTU Byg developed models for extended theoretical investigations: a) Solar electricity production assessment – a python tool was developed; The solar electricity assessment tool was verified with a public database. It can be utilized for holistic planning of stand alone solutions requiring electricity to power fans and pumps.b) system simulation utilizing solar thermal collectors – a TRNSYS spray evaporation model was developed. The TRNSYS model was successfully applied in a fist, simplified system scenario with a solar collector model and meteorological data from Nairobi, Kenya. Assumed parameters (performance of spray evaporation unit in dependency of ambient conditions) must be experimentally verified, then the model could be applied to design a spray evaporation system. Based on calculations results of the simplified system scenario, a stand-alone solution for zero liquid discharge is difficult to realise - experimental work is crucial to clarify applicability. All project results are documented in this report. Collected literature, developed simulation models and calculation sheets were made available to NoBiner for further development of brine management solutions.

In 2018 Brønderslev Forsyning inaugurated the world’s first power plant which combines concentrated solar power (CSP) and a biomass boiler to generate electricity using an Organic Rankine Cycle (ORC) turbine and utilizing the waste heat for district heating. This report presents an analysis of the monitoring results of the combined heat and power plant’s first three years of operation, as well as a simulation model of the system.First, an overview of the power plant is given in Section 1.1 and the solar collector field is described in detail in Section 1.2. Next, the monitoring results for the overall plant are given in Section 2, primarily focusing on the solar collector field. The performance of the solar collector is characterized in Section 3. Finally, in Section 4 a simulation model for the solar collector field is developed, validated, and used to investigate the impact of row spacing and collector field orientation.

Large solar collector fields are very popular in district heating system in Denmark, even though the solar radiation source is not favorable at high latitudes compared to many other regions. Business models for large solar heating plants in Denmark has attracted much attention worldwide. Denmark is not only the biggest country in both total installed capacities and numbers of large solar district heating plants, but also is the first and only country with commercial market-driven solar district heating plants. By the end of 2017, more than 1.3 million m2 solar district heating plants are in operation in Denmark. Furthermore, more than 70% of the large solar district heating plants worldwide are constructed in Denmark. Based on the case of Denmark, this study reviews the development of large solar district heating plants in Denmark since 2006. Success factors for Danish experiences was summarized and discussed. Novel design concepts of large solar district heating plants are also addressed to clarify the future development trend. Potential integration of large solar district heating plants with other renewable energy technologies are discussed. This paper can provide references to potential countries that want to exploit the market for solar district heating plants. Policy-makers can evaluate the advantages and disadvantages of solar district heating systems in the national energy planning level based on the know-how and experiences from Denmark.

In the period 2016-2017 the project “Availability of high quality weather data measurements” is carried out at Department of Civil Engineering at the Technical University of Denmark. The aim of the project is to establish measured high quality weather data which will be easily available for the building energy branch and the solar energy branch in their efforts to achieve energy savings and for researchers and students carrying out projects where measured high quality weather data areneeded.

The IEA joint Task 42 / Annex 29 is aimed at developing compact thermal energy storage materials and systems. In Working Group B, experts are working on the development of compact thermal energy storage applications, in the areas cooling, domestic heating and hot water and industry. The majority of application projects were in the field of room heating and domestic hot water. In this article, an overview is given of a large number of applications. The storage technologies used in the applications are latent heat storage, open and closed solid sorption, liquid sorption and salt hydrates and composites thereof. On a broad front, a lot of progress was made in the development of components and systems, providing knowledge and experience regarding the design, numerical modeling, building, testing and economical assessing of components and storage systems. Most important findings are that the interaction of storage materials with the materials of components can be deciding for the technical feasibility, that a number of components, like reactor, heat exchangers and evaporators are less understood than initially thought and need more development, that the inclusion of storage materials in systems generate new challenges like the occurrence of non-condensable gases and thermo-mechanical effects and that standardized and simplified system approaches are needed.