Earth Plastered Wall Heating as a Low-Emitting, Cost-Effective and Robust Energy System for Building Renovation

Renovation of the building stock in Europe is urgent to decrease the environmental impact from the building sector and meet the United Nations climate action goals. However, it is often hard to define a robust scenario for a renovation due to numerous uncertainties, which occur during the production, operation and end-of-life stage. One can cite the loss of performance of insulation and heating systems, the replacement time of installation or the future energy prices as well as the future climate. The replacement of oil boilers with heat pumps has shown a good performance regarding costs and greenhouse gas emissions. However, due to the flow and return temperature differences, often the current heat distribution system needs to be replaced as well, which is normally done with conventional radiators or floor heating. In this paper, we analyse a new possibility of a heat distribution system with earth plastered wall. We develop a methodology on the integrated assessment of life cycle assessment (LCA) and life cycle cost analysis (LCCA) for the renovation scenarios and adapt the analysis of the heat pump renovation solution with conventional radiators system and the earth plastered wall for two typical residential buildings located in Switzerland. Through rigorous statistical treatment, we then propagate the possible sources of uncertainty and perform the uncertainty quantification using polynomial chaos expansion to compare the distributions of two outcomes. The results show that the solution with the earth plaster has lower overall environmental impacts and costs. It has also been noticed that the solution with the earth plaster is more robust in investment cost and embodied emissions compared to the solution with the conventional radiators.

INDIVIDUAL DISTRIBUTION OF THERMAL ENERGY CONSUMPTION IN AN APARTMENT BUILDING: PRACTICAL EXPERIENCE

The cost of thermal energy production is constantly growing, on average, tariffs in the regions of Ukraine have tripled in recent years. The component of payment for heating in utility costs is the main one for most apartment buildings, but due to the peculiarities of district heating systems, residents do not have an impact on heat consumption, and there is a problem of uneven heat distribution: some rooms are overheated, others unheated. The normative documents of Ukraine indicate the installation of metering and regulation of energy consumption as one of the main measures to increase the level of energy efficiency of buildings. Modernization of heating engineering systems with the installation of thermostats and heat distributors is one of the most discussed energy saving measures at the general meeting of condominiums, which is of interest to most residents of buildings in operation. Experience shows that after the installation of such devices, the consumption of thermal energy by buildings is reduced, which leads to a reduction in heating costs. The relevance of the topic of this article is to study modern methods of individual distribution of thermal energy in apartment buildings, in particular in houses with a vertical heating system. The object of the study is an existing apartment building in Kyiv, where, starting in 2019, thermal energy distributors were put into operation. The subject of the study is the methods of heat distribution between apartments and the analysis of the practical results of the implementation of such a project in the existing serial building in Kyiv. The following research tasks were set: collection of general information about thermal energy distributors, their types and principles of operation; analysis of the current regulatory framework regarding the problem of individual accounting of thermal energy; analysis of the method of heat energy distribution adopted in Ukraine with identification of the main problems that arise during its application; analysis of practical results of thermal energy distribution in an apartment building in Kyiv.

The Effects of Absorbing Materials on the Homogeneity of Composite Heating by Microwave Radiation

When cured in a microwave, flat thin composite panels can experience even heat distribution throughout the laminate. However, as load and geometric complexity increase, the electromagnetic field and resulting heat distribution is altered, making it difficult to cure the composite homogeneously. Materials that absorb and/or reflect incident electromagnetic radiation have the potential to influence how the field behaves, and therefore to tailor and improve the uniformity of heat distribution. In this study, an absorber was applied to a composite with non-uniform geometry to increase heating in the location which had previously been the coldest position, transforming it into the hottest. Although this result overshot the desired outcome of temperature uniformity, it shows the potential of absorbing materials to radically change the temperature distribution, demonstrating that with better regulation of the absorbing effect, a uniform temperature distribution is possible even in non-uniform composite geometries.

Quantum–Classical Correspondence Principle for Heat Distribution in Quantum Brownian Motion

Quantum Brownian motion, described by the Caldeira–Leggett model, brings insights to the understanding of phenomena and essence of quantum thermodynamics, especially the quantum work and heat associated with their classical counterparts. By employing the phase-space formulation approach, we study the heat distribution of a relaxation process in the quantum Brownian motion model. The analytical result of the characteristic function of heat is obtained at any relaxation time with an arbitrary friction coefficient. By taking the classical limit, such a result approaches the heat distribution of the classical Brownian motion described by the Langevin equation, indicating the quantum–classical correspondence principle for heat distribution. We also demonstrate that the fluctuating heat at any relaxation time satisfies the exchange fluctuation theorem of heat and its long-time limit reflects the complete thermalization of the system. Our research study justifies the definition of the quantum fluctuating heat via two-point measurements.