Minimizing costs is easier than minimizing peaks when supplying the heat demand of a group of houses

This paper studies planning problems for a group of heating systems which supply the hot water demand for domestic use in houses. These systems (e.g. gas or electric boilers, heat pumps or microCHPs) use an external energy source to heat up water and store this hot water for supplying the domestic demands. The latter allows to some extent a decoupling of the heat production from the heat demand. We focus on the situation where each heating system has its own demand and buffer and the supply of the heating systems is coming from a common source. In practice, the common source may lead to a coupling of the planning for the group of heating systems. On the one hand, the external supply of the energy for heating up the water may have to be bought by an energy supplier on e.g. a day-ahead market. As the price of energy varies over time on such markets, this supplier is interested in a planning which minimizes the total cost to supply the heating systems with energy. On the other hand, the bottleneck to supply the energy also may be the capacity of the distribution system (e.g. the electricity networks or the gas network). As this has to be dimensioned for the maximal consumption, in this case it is important to minimize the maximal peak. The two mentioned coupling constraints for supplying the energy for producing the heat, lead to two different objectives for the planning of the group of heating systems: minimizing cost and minimizing the maximal peak. In this paper, we study the algorithmic complexity of the two resulting planning problems. For minimizing costs, a classical dynamic programming approach is given which solves the problem in polynomial time. On the other hand, we prove that minimizing the maximal peak is NP-hard and discuss why this problem is hard. Based on this, we show that this problem becomes polynomial if all heating systems have the same consumption of energy when turned on. Finally, we present a Fix Parameter Tractable (FPT) algorithm for minimizing the maximal peak which is linear in the number of time intervals

High temperature proton exchange membrane fuel cells control for combined heat and power applications

Over the last few years, the research of new energy sources as a substitute for the current de-pletable ones has been increasing. One of these possible sources is hydrogen, one of the mostcommon elements in the planet. By using what’s called as a fuel cell, it can be used to efficientlygenerate clean electrical and thermal energy, as the only output is water.This project has been developed in the framework of the DPI2015-69286-C3-2-R MICAPEM (Pa-rameter estimation, diagnosis and control for the improvement of efficiency and durability ofPEM fuel cells) project, which aims to create an architecture and control of a system that will beable to supply electrical and thermal power to a typically-sized house using a Proton ExchangeMembrane Fuel Cell working at high-temperature (HT-PEMFC).To do so, a Model Predictive Control (MPC) will be used, capable of controlling the amountof hydrogen being consumed based on the prediction of the house’s electrical and thermal de-mand.The numerical computation system Matlab will be used for the creation of the MPC and itsSimulink tool, to model the PEMFC system. Then a series of simulations will be run, which willboth test the controller in several scenarios as well as to understand its behaviou

Roadblocks to low temperature district heating

Energy usage in buildings is coming increasingly under the spotlight as carbon policy focus shifts towards the utilization of thermal energy. In the UK, heating and hot water accounts for around 40% of energy consumption and 20% of greenhouse gas emissions. Heating is typically produced onsite, making widescale carbon or energetic improvements challenging. District heating networks (DHNs) can offer significant carbon reduction for many users but can only be implemented if the end user buildings have good thermal energy efficiency. This greatly limits the ability to implement advancing 4th and 5th generation DHNs, which are the most advanced systems available. We elucidate the current state of thermal efficiency in buildings in the UK and provide recommendations for necessary building requirements and modifications in order to accommodate 4th and 5th generation district heating. We conclude that key sectors must be addressed including creating a skilled workforce, producing relevant metrics and benchmarks, and providing financial support for early stage design exploration

Carbon-Free Power

There is a new world order in electrical energy production. Solar and wind power are established as the low-cost leaders. However, these energy sources are highly variable and electrical power is needed 24/7. Alternative sources must fill the gaps, but only a few are both economical and carbon-free or -neutral. This book presents one alternative: small modular nuclear reactors (SMRs). The authors describe the technology, including its safety and economic aspects, and assess its fit with other carbon-free energy sources, storage solutions, and industrial opportunities. They also explain the challenges with SMRs, including public acceptance. The purpose of the book is to help readers consider these relatively new reactors as part of an appropriate energy mix for the future and, ultimately, to make their own judgments on the merits of the arguments for SMRs.Publishe