The thermal pyrolysis of agriculture biomass has been studied in a fixed-bed reactor, where the pyrolysis was conducted at a steady temperature of 800 °C. This work analyses the pyrolysis products of six agricultural wastes: pistachio husks, walnut husks, sunflower hulls, buckwheat husks, corncobs and coconut shells. The conducted research compared examples of large waste biomass streams from different parts of the world as a potential source of renewable energy. Additionally, the kinetics of the reaction with the activation energy were analyzed and calculated for all raw materials in pyrolysis process. Biochars are characterised by higher combustion heat in comparison to the raw material samples. The average value of the heat of combustion increased due to pyrolysis process from 10 MJ/kg, with minimal value of 2.7 MJ/kg (corncob) and maximum of 13.0 MJ/kg for coconut, which is also characterised by the maximal absolute combustion heating value (32.3 MJ/kg). The increase in calorific values varied from 15% to 172% (with 54% reference for wood chips), which indicates that charring is an effective method for increasing the energy concentration. The obtained biochar were compared with wood chips, which are widely used solid fuel of organic origin. The studied biomass-derived fuels are characterised by lower ash contribution than wood. An analogous observation was made for the obtained biochars, whose ash contribution was lower than for the chips in terms of both unit-mass and unit-combustion-heat. The main advantage of this method is the production of solid fuel from biomass, which increases the calorific value and bulk density of biochar in comparison to raw material.

Adsorption cooling and desalination technologies have recently received more attention. Adsorption chillers, using eco-friendly refrigerants, provide promising abilities for low-grade waste heat recovery and utilization, especially renewable and waste heat of the near ambient temperature. However, due to the low coefficient of performance (COP) and cooling capacity (CC) of the chillers, they have not been widely commercialized. Although operating in combined heating and cooling (HC) systems, adsorption chillers allow more efficient conversion and management of low-grade sources of thermal energy, their operation is still not sufficiently recognized, and the improvement of their performance is still a challenging task. The paper introduces an artificial intelligence (AI) approach for the optimization study of a two-bed adsorption chiller operating in an existing combined HC system, driven by low-temperature heat from cogeneration. Artificial neural networks are employed to develop a model that allows estimating the behavior of the chiller. Two crucial energy efficiency and performance indicators of the adsorption chiller, i.e., CC and the COP, are examined during the study for different operating sceneries and a wide range of operating conditions. Thus this work provides useful guidance for the operating conditions of the adsorption chiller integrated into the HC system. For the considered range of input parameters, the highest CC and COP are equal to 12.7 and 0.65 kW, respectively. The developed model, based on the neurocomputing approach, constitutes an easy-to-use and powerful optimization tool for the adsorption chiller operating in the complex HC system.

Modern distribution grids may suffer problems of voltage distortion, especially along radial low-voltage feeders with a high penetration of intermittent, unbalanced and distorted loads and generation sources. It is a challenge to develop an effective voltage-regulation method using a straightforward implementation. This paper proposes a novel method for local voltage control and balancing using a shunt-connected energy storage system. The compensation principles are explained, and a complete controller design is proposed. The algorithm is designed to be implemented in power electronic converters that provide the interface between the storage and the grid. The original contribution is the development of a low-level control method, which includes voltage balancing and a method to minimize the compensator current and is to be implemented in power electronic converters that provide the interface between the storage and the grid. The calculation of active and reactive compensator currents is explained with relation to the estimated grid impedance. The efficacy of the designed controller is verified by laboratory experiments. It is shown that voltage regulation using the proposed method is achieved with less apparent power compared to a system where only reactive power is used. The controller presents a very good dynamic response to rapid voltage variations, such as unbalanced voltage dips. The applicability and constraints of the method are discussed with respect to the present state of the art in low-voltage-grid voltage regulation.

Solar-powered adsorption chillers are a particularly interesting alternative to energy-intensive conventional refrigeration systems. Integration of the adsorption chiller with solar collectors is a very promising concept since the increase in solar radiation coincides with the increased demand for cooling. Such a solution is very economical and environmentally friendly. It also fits in with current trends related to energy policy and sustainable development. The article presents the results of tests conducted for a two-bed adsorption chiller integrated with solar collectors. The tests were performed on selected days of the summer period (July and August) at the KEZO Research Centre PAS in Jablonna (Poland). Based on the results obtained, the performance parameters of the adsorption chiller were determined, and the problems associated with the integration of all components of the system were identified and discussed. The values of the determined Coefficient of Performance (COP) and cooling capacity for the tested adsorption chiller are, depending on the day on which the tests were conducted, from 0.531 to 0.692 and from 5.16 kW to 8.71 kW, respectively. Analysis of the test results made it possible to formulate conclusions related to the design of integrated systems of adsorption chillers with solar collectors.

A photovoltaic thermal solar collectors (PVT) and heat pump combined system consists of numerous elements. In this context it is important to properly model respective elements. To the best of our knowledge there is no relative research that has optimized PVT geometry to maximize heat generation for the ground regeneration. Therefore, the authors decided to investigate the influence of bottom insulation and air gap thickness on heat generation in case of glazed and unglazed PVT. The results show that the optimum construction of the PVT should be based on the unglazed technology of solar collector and on minimum insulation thickness. Obviously, the thickness of insulation needs to be optimized to the specific conditions like for instance type and depth of borehole heat exchangers or parameters of the heat pump.