A highly innovative yet cost-effective multi-generation energy system for net-zero energy buildings

Performance evaluation and financial analysis of applying hybrid renewable systems in cooling unit of data centers – A case study

Model predictive control under weather forecast uncertainty for HVAC systems in university buildings

Optimize heat prosumers' economic performance under current heating price models by using water tank thermal energy storage

Thermal energy storage sizing for industrial waste-heat utilization in district heating: A model predictive control approach

https://escholarship.org/content/qt20s461nc/qt20s461nc.pdf?t=qt8zvy

Energy, economic, and environmental analysis of integration of thermal energy storage into district heating systems using waste heat from data centres

Low temperature is the most significant feature of the future district heating system- the 4th generation district heating (4GDH). However, a widely used control strategy for supply water temperature in substation is weather- compensated control. It is a feedforward control without any dynamic information about buildings, which can lead to higher or lower supply water temperature. This paper presents model predictive controller (MPC) applied to the supply water temperature control for substations in district heating systems. MPC is an advanced control technique, which can make full use of dynamic information of buildings to determine the optimal supply water temperature of substations. In this paper, a multiple inputs and single output dynamic model was identified by subspace methods. Two different MPC controllers were designed in Simulink. The MPC controller 1 focused on keeping indoor air temperature at reference values. The MPC controller 2 focused on both keeping indoor air temperature at reference values and tracking the minimum supply water temperature in order to find the temperature potential for the future DH systems. Both of the MPC controllers proved to have a better tracking effect for indoor air temperature and lower average supply temperatures compared to weather- compensated. The MPC controller 2 could further lower supply water temperature compared to the MPC controller 1 by tracking minimum supply water temperature in its objective function. The average supply water temperatures for the weather- compensated, the MPC controller1, and the MPC controller 2 were 52°C, 51°C and 50°C, respectively. The results showed that MPC has a great potential in the area of supply water temperature control of the district heating systems.

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Optimal control of secondary side supply water temperature for substation in district heating systems

Peak load has significant impacts on the economic and environmental performance of district heating systems. Future sustainable district heating systems will integrate thermal storages and renewables to shave their peak heat demand from traditional heat sources. This article analysed the techno-economic potential of implementing thermal storage for peak load shaving, especially for the district heating systems with waste heat recovery. A campus district heating system in Norway was chosen as the case study. The system takes advantage of the waste heat from the campus data centre. Currently, about 20% of the heating bill is paid for the peak load, and a mismatch between the available waste heat and heat demand was detected. The results showed that introducing water tank thermal storage brought significant effects on peak load shaving and waste heat recovery. Those effects saved up to 112 000 EUR heating bills annually, and the heating bill paid for the peak load could be reduced by 15%. Meanwhile, with the optimal sizing and operation, the payback period of the water tank could be decreased to 13 years. Findings from this study might help the heat users to evaluate the economic feasibility of introducing thermal storage.

/pdf/techno-economic-analysis-of-implementing-thermal-storage-for-4qqte1r7qt.pdf

Techno-economic analysis of implementing thermal storage for peak load shaving in a campus district heating system with waste heat from the data centre

Juan Hou

Papers

Energy, economic, and environmental analysis of integration of thermal energy storage into district heating systems using waste heat from data centres

Optimize heat prosumers' economic performance under current heating price models by using water tank thermal energy storage

Optimal control of secondary side supply water temperature for substation in district heating systems

Techno-economic analysis of implementing thermal storage for peak load shaving in a campus district heating system with waste heat from the data centre