Search

Cogeneration systems based on internal combustion engines (ICE) provide decent efficiency and flexibility. In order to further improve the efficiency, organic Rankine cycle (ORC) can be used to convert high temperature (waste) heat from flue gas to electricity. There is a large amount of heat in jacket cooling at lower temperatures for which there is often no demand so it has to be rejected into the ambient. Previous systems trying to utilise this heat in the ORC cycle end up as too complex and expensive. This study introduces an innovative jacket cooling method. In the cooling system of an ICE, instead of typical water or oil-based heat transfer fluids, the working fluid of an ORC is used as the engine coolant, recovering the low-potential heat. Preheated organic fluid is then directly used in the bottoming ORC with further heat input from the flue gas. This concept allows utilising both low and high potential heat from the cooling of the ICE and from the flue gas recovery, while omitting the intermediate heat-transfer circuits commonly found in ORC waste heat recovery applications. Presented thermodynamic analysis shows a strong dependency of the ORC utilisation efficiency on cooling fluid allowed pressure in the ICE jacket and on the heat flow ratio between the coolant and the flue gas of the ICE. A baseline study with a specific 83 kWe ICE with the novel configuration provides an improvement of nearly 10 kW in comparison with 7 kW of an ORC utilising only flue gas. More general parametric analysis has shown the potential of the ORC power output improvement by more than 60% for specific ICE types and higher pressures and temperatures in the engine cooling circuit. In a cogeneration regime, these benefits in electrical power output come at the cost of a very slight decrease in overall efficiency.

This paper provides an insight into the early commercial development and pilot operation of a 50 kW thermal and 2 kW electrical output biomass-fired microcogeneration (μCHP) ORC unit. The aim of this work is to share the experience and the field data from the pilot installation of this unit in a village where it provides the heat and electricity for municipality buildings. The transition from the laboratory unit into the commercial one are discussed. The μCHP ORC unit, though initially burdened by some issues, successfully operated in the first two heating seasons and reached the parameters of the laboratory twin unit. The unit was so far operated for over 3000 h, reaching total heat production of 125 MWh and gross electricity production of 2.34 MWh. The operational data from the first two heating seasons are presented along with issues (especially regarding expander reliability) and the development towards their mitigation. Economic considerations of investment into biomass μCHP ORC system are discussed. The different paradigm that authors adopted shows that economic performance cannot be the only parameter for investment evaluation, but the investor needs to assess additional benefits from the μCHP system while implementing the cost-benefit analysis.

Micro-cogeneration technologies currently available on the market are too expensive and requiring noble and expensive fuels. Also increasing renewables' shares should favour biomass as a cheap local and available fuel providing dispatchable power. We present a renewable solution based on woodchip combustion system coupled with ORC for applications replacing biomass boilers and producing electricity for own system consumption and a little bit extra. This work describes the design methodology as a complex issue from not only thermodynamic and technical perspective, but also economical and legal. Finally, the technical specifications and operational characteristics of the constructed micro-cogeneration ORC biomass fired system which is in a pre-pilot application stage are presented. This work follows as an extension and follow-up on a paper presented in IV International Seminar on ORC Power Systems, ORC2017, 13–15 September 2017, Milano, Italy.

Organic Rankine cycles (ORC) are efficient technologies for waste heat recovery (WHR) at low to mid temperatures. For the design of ORC power cycles, several thermodynamic parameters should be considered. A challenge related to small scale (

Absorption power cycle (APC) using water-lithium bromide (LiBr) as a working fluid is a novel concept especially suitable for micro scale low temperature distributed power systems. Theoretical investigations provide various benefits in comparison to alternatives such as organic Rankine cycles, but technical design poses many challenges as well. Regardless of similarities with LiBr absorption chillers, no LiBr APC has been to authors’ knowledge experimentally operated. This paper focuses on an experimental development of a proof-of-concept APC operating with LiBr solution. The first part contains an introduction of the experimental system built, the first tests and experimental results of the cycle. The main part of this work focuses specifically on the expander design and performance. After discussing turbine considerations, axial steam micro turboexpander with plastic 3D printed components (rotor and stator) with design power output of approx. 300 W is described. Experimental performance is presented and compared to the design point.

This work introduces a modular experimental micro turboexpander system designed to perform air turbine tests of a radial impulse cantilever turbine. The system has high modularity and is intended primarily to test flow-path components which are manufactured by 3D printing and rapid prototyping. System design from the fluid dynamic viewpoint is based on a previously described tool proven and validated during the design of micro turboexpanders in range of mainly dozens of kW. In order to achieve maximal simplicity, the system uses a converted aeromodelling motor as a permanent magnet generator and housing for bearings. Overall parameters are obtained from electrical performance and known generator’s characteristics. The mechanical design then takes into account request of simplicity, modularity and properties of materials in additive manufacturing, especially plastics. First experimental tests show a comparison between different manufacturing technologies and resulting flow components surface roughness and the impact of pressure ratio on the isentropic efficiency.

Absorption cycles have been proposed not only for cooling but also for power generation. Most common is then Kalina cycle utilizing water-ammonia mixture working fluid. Other working fluids theoretically may provide thermodynamic benefits, have only rarely been examined experimentally. This work reports on, to the authors��� knowledge, the world���s first absorption power cycle using salt solution (here aqueous solution of LiBr), known so far only from absorption cooling. The system with a design power output of around 300 W features solutions such as a nylon 3D printed turbine or measurement of temperature glide during phase change in the heat exchangers. This work is focused on an analysis of the experimental performance of the system. The measured turbine efficiency reached 25% with a potential for much higher values with better design. Over the range of explored conditions, if 65% expander performance was assumed, the maximal cycle efficiency could be around 4.5% and utilization efficiency 0.5%.

Non-condensable gases (NCG) in condensing geothermal flash plants have negative effects as they reduce heat transfer and thus deteriorate vacuum in condenser. Therefore, it is necessary to evacuate the condenser by vacuum pumps which substantially increases the parasitic load of the plant. Furthermore, NCG consist mostly of CO2 and H2S, gases for which methods of abatement are being searched for. In such case, further compressors or blowers are usually required to push the gas through absorption systems.Alternative methods of NCG separation consider a reboiler upstream of a turbine. This process is however connected with significant loss of steam enthalpy, moreover the NCG in high content have also certain work potential. Therefore, this method is often not considered as very perspective.We are proposing a novel solution where the turbine is split in two parts at high and low pressure. The splitting point is at a pressure right above an ambient pressure, wherein a reboiler is placed. By doing so the NCG stream is easily obtained without energy penalty of vacuum pumps, without decreasing turbine admission parameters, and also utilizes its pressure potential. This stream is thus easily ready for processing and subsequent CO2 separation and conditioning. Condensed water is from large part turned back to steam in the cold side of reboiler which gives further work in low pressure turbine with achievable lower backpressure and therefore potential for higher power production. Another advantage of this method is liquid phase elimination from the turbine thus achieving higher turbine efficiency. Keywords: Geothermal, Emissions, CO2, Non-condensable gases, Flash plant, Reboiler

Development of micro ORC systems with 1-15 kW power output for micro-cogeneration and waste heat recovery at the Czech Technical University in Prague, University Centre for Energy Efficient Buildings (CTU UCEEB) has over ten years of history with many successes. These include 6 different ORC units, all with in-house designed rotary vane expanders (RVE) of many versions throughout this development. Among main advantages of the RVE belong relatively simple and robust design at low cost even at very small series of single-unit production and all that with acceptable efficiency. The ORC units operate with hexamethyldisiloxane (MM) working fluid at high pressure ratios and expansion ratios and the isentropic efficiency of RVE has a limit at these conditions around 60%, often however only at values around 50%. While this might be enough on a cost side for commercialization of this technology, in pursuit of higher efficiency solutions, different expander technology needs to be selected. A turbo-expander is a logical choice with prospect of higher efficiency. At the same time, a literature review has found a lack of reported detailed experimental data for micro (5-50 kW) turbo-expanders, possibly hindering global development towards economically feasible solutions. A project named Dexpand, “Optimised expanders for small-scale distributed energy systems” aims at these issues by objectives in designing, optimizing, manufacturing and testing several ORC expanders with MM and isobutane and their subsequent performance mapping and comparison. One major task is a design of a turboexpander for a 120 kWth biomass fired microcogeneration ORC unit currently operated at the CTU UCEEB. An axial impulse single stage turboexpander was selected as a suitable choice, providing a prospect of a decent efficiency at technically manageable rotational speed and size. This paper provides a detail of currently performed design activities, starting from boundary conditions specification, over development and optimization of a 1D model, preliminary 2D CFD calculations and finishing in a state of a robust and detailed 3D CFD model with a real gas model. Note that the working fluid, high molar mass organic vapour, is highly non-ideal in its behaviour and the flow conditions with pressure design ratio around 13 is highly supersonic (nozzle outlet isentropic Mach number exceeds 2). The current results based on 3D CFD indicate a prospect of an isentropic efficiency 71% at mechanical power output of 11 kW. Lastly, ongoing and future work is outlined, which includes aerodynamic optimization based on the developed 3D CFD model and construction design of the entire turbine assembly.

Combined systems for power production and thermally activated cooling have a high potential for improving the efficiency and utilisation of thermal systems. In this regard, various configurations have been proposed and are comprehensively reviewed. They are primarily based on absorption systems and the implementation of multiple levels of complexity and flexibility. The configuration of the absorption power and cooling combined cycle proposed herein has wide commercial applicability owing to its simplicity. The configuration of the components is not new. However, the utilisation of aqueous salt solutions, the comparison with ammonia chiller and with absorption power cycles, the focus on parameters that are important for real-life applications, and the comparison of the performances for constant heat input and waste heat recovery are novel. The proposed cycle is also compared with a system based on the organic Rankine cycle and vapour compression cycle. An investigation of its performance proves that the system is suitable for a given range of boundary conditions from a thermodynamic standpoint, as well as in terms of system complexity and technical feasibility. New possibilities with regard to added power production have the potential to improve the economics and promote the use of absorption chiller systems.

Micro-cogeneration and small scale waste heat recovery has its place in the concept of sustainable future and distributed electricity generation as it should provide environmental, economical and social advantages. ORC belongs among perspective technologies to achieve a successful commercialization. Domain of power output below 10 kW is particularly interesting because it brings a possibility of energy production to a wide range of potential customers. Widespread of solid fuels fired heating systems and a desire for renewable energy suggest a combination of biomass and cogeneration systems. There is an eight-year history of an ORC development at the Czech Technical University aiming at applications for cogeneration and waste heat recovery with power output between 1 and 10 kW. This work shows the overall development over four different ORC units. Development of different concepts, configurations or choice of technologies is presented in this work together with the obtained performance parameters. Common feature of all presented units are use of rotary vane expander (of which three different generations have been designed and tested).

A pump is a necessary component of ORC units. Although it is simple in a principle and various pump types can be used, reality may easily bring many complications. When designing an ORC for very low power output applications (1-10 kW gross power production), problems such as leakages, mechanical and electrical losses are more significant. Using a tight and reliable pump, typically of a diaphragm type, results in extremely low efficiency, which negatively affects the overall cycle performance. We propose for micro ORC units a gear pump. Typical losses in a gear pump and their contributions with respect to issues that need to be overcome (hermetic seal requirement, reliability and overall efficiency) are described in general in the first part of this paper. The losses are volumetric, mechanical and also electrical of motor and variable frequency drive. In the second part of the paper we present the measured characteristics of the modified commercially available gear pump. The pump is intended for an ORC with a net power output of 1-10 kW. Characteristics are given for both a standalone pump and the pump coupled with an asynchronous motor. They show significantly higher efficiency than typically reported in the literature. Contribution of different losses is discussed. Mechanical losses influence operation of the pump at low pressures (lower hydraulic work but nearly constant power input) while volumetric losses at higher pressure have only small effect. The largest loss comes from electrical efficiencies of motor and variable frequency drive, especially for operation at low speed. Optimizing the operating conditions of the pump together with the motor is therefore the most important in terms of reducing pump power consumption.

Volumetric expanders are used for low to medium power output ORC applications. For low power output ORCs ( This work describes a semi-empirical model with two different leakages – lumped leakage area between inlet and outlet and leakage between working chambers due to delayed contact of vane and stator. Primary purpose of the model is to demonstrate the effect of the delayed chamber closure. This is identified as a necessary parameter for modeling of the rotary vane expanders, compared to only single lumped leakage area for the other expander types. Results of the model for several case scenarios are presented, showing an impact of these leakages on an overall cycle performance, isentropic efficiency and filling factor. It is demonstrated that isentropic efficiency of the rotary vane expander might not be always sufficient to compare vane expanders or their modifications even within a same ORC. Lastly the model conclusions are preliminarily checked with our experimental data.

Absorption power cycles (APC) provide an alternative to the ORC as an interesting thermodynamic cycle for waste heat recovery. Particular advantage of the APC is in a multicomponent working fluid that allows for a temperature glide along boiling and condensation (desorption and absorption). This phenomenon provides a good temperature match of hot and cold streams in the heat exchangers during the phase change. Thus it is possible to achieve higher exergy efficiency of the heat addition when sensible heat is used as a heat source. Similarly good temperature match and lower cooling fluid flow through absorber-condenser for heat rejection lowers the parasitic load of fans or cooling tower pumps. As a result, higher net efficiency can be achieved in comparison to a single component working fluid. In the past, the only considered APC has been Kalina cycle operating with water-ammonia mixture as a working fluid, while other fluid combinations were only rarely considered. Recently there came into an attention an aqueous solution of Lithium Bromide (LiBr), typically known from absorption cooling. Compared to ammonia-water mixture the pressure levels in the cycle are very low, typically both high and low pressure in vacuum. This results in high volumetric flow, bulky device, but when turbine is used it can achieve high efficiency and increased material cost are for small units is only of a marginal importance. In this study after the introduction of theoretical advantages in efficiency and of design features and constraints, we present results of several case studies for potential application. These are waste heat recovery from hot air stream, low temperature geothermal application, coupling with vacuum solar collectors, bottoming cycle for ORC and a combined cooling and power cycle as an alternative to the cooling-only absorption cycle.

Implementation of CCS technologies into fossil power plants brings inevitable technical, energy and economic penalty. This penalty increase when low rank coals as lignite are utilized. The efficiency loss results in larger amounts of waste heat rejected into the ambient as it cannot be reasonably utilized within the power cycle. The temperature of the waste heat in some cases is however still sufficient for conversion to electricity by small modular waste heat recovery (WHR) units based on technologies such as Organic Rankine Cycle and absorption power cycle. Three generally considered CCS technologies were modelled – oxyfuel combustion and ammonia scrubbing based post-combustion (subcritical power plant with fuel drying) and pre-combustion (IGCC with Rectisol method for CO2 separation), for which the WHR options have been analyzed. Systems with WHR improve plant efficiency, but also flexibility due to decoupling waste heat streams from the main steam cycle. Results are presented for scenarios of 250 MWe coal fired power plants, applied to central European conditions. The efficiency increase in the case of an IGCC-CCS plant is up to 4.2 percentage points, followed by oxyfuel with 1.3 percentage points while effectiveness in post-combustion is minimal, 0.1 percentage points. The economic effect is positive in all CCS plants, allowing for improvements in the LCOE by up to 6.3%.

Customization and providing tailored products, while keeping highly automated production with minimum manufacturing personnel, is a general trend, and one of the expectations of manufacturing companies from developed countries to stand in competition against cheap mass production. This trend, often also called “industry 4.0”, is taking advantage of many innovative and quickly developing technologies like AM or 3D printing. Applications of 3D printing are also getting into the field of turbomachinery. The first part of the paper provides a review of current 3D printing technologies with respect to applications in turbomachinery field. Several technologies, mostly for producing a metal or plastic product, exist and can be considered. Applications for the components range from single Watts to hundreds MW scale and similarly for various other operating conditions. The second part briefly describes possible practical applications concerning multiple situations as research and development, customization of end-product, operative field-testing, or temporary replacements.

Greater expansion of distributed power and process systems based on thermodynamic cycles with single to hundred kW scale power output is limited mainly there are not available cost-effective expanders. Turboexpanders have a perspective of high efficiency and flexibility concerning operating parameters even for the micro applications. However, they suffer from a high manufacturing cost and lead time in the development of traditional technologies (such as casting and machining processes). Additive manufacturing provides a possibility to overcome some of the issues. Manufacturing parts with complicated shapes by this technology, combining multiple components into a single part or rapid production by 3D printing for development purposes are among the prospective features with this potential. On the other hand, the 3D printing processes come with certain limitations which need to be overcome. This paper shows a design and manufacturing process of a 3 kW axial impulse air turbine working with isenthalpic drop 30 kJ/kg. Several samples to verify printing options and the turbine itself has been manufactured from stainless steel by the DMLS additive manufacturing method. Manufactured are two turbine variations regarding blade size and 3D printer settings while maintaining their specific dimensions. The turboexpanders testing method and rig is outlined. As the surface quality is an issue, several methods of post-processing of 3D printed stator and rotor blading to modify surface quality are suggested. Detailed experimental investigation is however subject of future work.

This paper compares the techno-economic performances of three technologies for CO2 capture from a lignite-based IGCC power plant located in the Czech Republic: (1) Physical absorption with a Rectisol-based process; (2) Polymeric CO2-selective membrane-based capture; (3) Low-temperature capture. The evaluations show that the IGCC plant with CO2 capture leads to costs of electricity between 91 and 120 €$MWh–1, depending on the capture technology employed, compared to 65 €$MWh–1 for the power plant without capture. This results in CO2 avoidance costs ranging from 42 to 84 €$tCO2,avoided –1 , mainly linked to the losses in net power output. From both energy and cost points of view, the low-temperature and Rectisol based CO2 capture processes are the most efficient capture technologies. Furthermore, partial CO2 capture appears as a good mean to ensure early implementation due to the limited increase in CO2 avoidance cost when considering partial capture. To go beyond the two specific CO2-selective membranes considered, a cost/membrane property map for CO2-selective membranes was developed. This map emphasise the need to develop high performance membrane to compete with solvent technology. Finally, the cost of the whole CCS chain was estimated at 54 €$tCO2,avoided –1 once pipeline transport and storage are taken into consideration. © Higher Education Press and Springer-Verlag GmbH Germany, part of Springer Nature 2019

Summary There are many low-temperature heat sources; however, current technologies for their utilization have a relatively low efficiency and high cost. The leading technology in the low-temperature domain for heat-to-work conversion is the organic Rankine cycle (ORC). Absorption power cycles (APCs) are a second option. Nearly all currently known APCs, most importantly the Kalina cycle, use a water-ammonia mixture as their working fluids. This paper offers a theoretical exploration of the possibility of utilizing aqueous solutions of three salts (lithium bromide, lithium chloride and calcium chloride), known mainly from absorption cooling, as working fluids for APCs. The cycles are compared with a typical steam Rankine cycle, a water-ammonia APC, and (subcritical) ORCs with a range of working fluids explored. The analysis includes a parasitic load for heat rejection by a cooling tower or air-cooled condenser. The absorption cycles exhibit better performance than all Rankine-based cycles analysed in temperatures below 120°C. For the LiBr-based APC, a detailed thermal design of the cycle is provided for 100°C water as a heat source and a sensitivity analysis is performed of the parameters controlling the main cycle. Mechanical design considerations should not pose a problem for small power units, especially in the case of expansion machines, which are often problematic in ORCs. The salt-based APCs also carry environmental benefits, as the salts utilized in the working fluids are non-toxic. Copyright © 2016 John Wiley & Sons, Ltd.

Forward osmosis (FO) for desalination is receiving tremendous attention due to its low energy consumption and simple operation compared to reverse osmosis. Here, we propose a thin-film nanocomposite (TFN) membrane with vertically embedded carbon nanotubes (CNTs) in the active layer to maximize membrane permeability without significantly sacrificing selectivity. We first attempted a spray-assisted electromagnetic field alignment technique to vertically embed CNT in the active layer of the TFN membrane. After vertically embedding the CNT, the developed TFN membrane exhibited 20% increased water flux. When chemical etching of the active layer was further applied, increase in water flux was over 300% (40 LMH). Meanwhile, the increased reverse salt flux was mild most likely due to the steric effect of CNT in the active layer. The developed TFN membrane, thus showed even higher water flux and lower reverse salt flux when compared to recently provided commercial FO membranes. This method is easy to up-sc...

Rotary vane expander (RVE) is a perspective type of a volumetric expander for small series manufacturing due to its simple geometry and low manufacturing costs. Performance of this type of expander is usually worse in comparison with other volumetric expanders but it can be improved if we understand well the phenomena that occur during expansion within the vane expander. This work provides a theoretical and experimental analysis of the influence of various leakage pathways on the behaviour of a RVE. The RVE used in this work has been specifically modified for the possibility of adjusting the axial and radial clearances. Experimental data for the both clearances ranging from +0 to +0.5 mm were used to set up a 1D mathematical model, which, provides accuracy of parameter prediction within ±5%. Such model can be further used for optimization and design of RVE. In this paper, the model was used to analyse the effect of reducing manufacturing tolerances on the expander parameters. Analyses are performed for constant pressure difference (common in literature), as well as for the regime of constant heat input of the thermodynamic cycle (better reflects the conditions of the real expander operation and its effect to the entire cycle).

This work shows aspects of integrating decentralized electricity production systems based on small scale heat and power cogeneration (CHP) systems. On a case study of replacement of old brown-coal heating system is shown an important fact that these technologies can't be considered as standard investment but as a necessity to secure heating requirements for manufacturing processes, administrative or residential buildings. Impact is on investor's decision making, which may be significantly different from techno-economic optimization and typical discounted cash flow assessment. When risks are included, the decision making process is more complicated. When the projects have same discounted expenses over the period of comparison then the option with lowest CAPEX would be selected. The work analyses several illustrative options of risk and a benchmark option for the comparison.

Virtual power plants using spare capacity of standing plugged-in electric vehicles (EV) is an innovative system which will be able to cope with power grid instabilities brought by intermittent renewables. Bottleneck for its application is however the widespread of EV, being stuck at the chicken or the egg causality dilemma of charging infrastructure presence and larger customers' demand for EVs. This paper shows a concept and case study for a district — to city — scale integrated system bringing EV charging infrastructure in large scale with low visual impact even into densely populated areas and in a way economically feasible for larger investors.

Absorption power cycle (APC) working with LiBr-H2O solution as a working fluid has been recently identified as a prospective option power production for low temperature and small output (1-10 kW) applications. Different boiling temperatures of the solution components cause a temperature glide during evaporation and condensation (instead of isothermal process for single-component fluid), which can decrease exergy losses during heat exchange processes. The cycle can also operate in a regime of partial power production and partially as an absorption chiller.Thermodynamic properties of the working fluid give a very interesting performance in comparison to ORC as well as standard Kalina cycle. On the other hand the whole cycle (high and low pressure) operates at sub-ambient pressure with large volumetric flows. However, this gives a potential for high turboexpander efficiency for power output in order of several kW. This concept of APC also brings many challenges for the real-life system as actual temperature profile in heat exchangers with temperature glide phase change, purity of the steam going to the expander concerning the liquid solution droplets, actual air tight operation and limiting of corrosion in the system.Therefore and experimental rig for validation of these aspects has been built. Its specific design, methods for components’ sizing and first experimental results which tackle some of the mentioned challenges are presented in this work. Results are presented for design of experimental desorber, vapour separator and general system of the rig which has been built in current phase of larger experimental intentions. First results with water instead of LiBr solution give suggestions of required desorber configuration. Expander, absorber or eventually also parallel absorption chiller operation is under planning as a future work.

This chapter introduces absorption power cycles (APC) as a perspective option for power production from low-temperature heat. The multicomponent mixture working fluid can provide low exergy destruction in heat exchangers through variable temperature phase change, thus achieve higher efficiency than alternatives such as ORC. Except for commonly known Kalina cycle using NH3-H2O mixture, there is a wide choice of other absorbent-absorbate pairs. This work theoretically explores APC with various types of working fluids compared with ORC (also several configurations and working fluids). Potential of APC is mainly in small systems for low-temperature heat sources around 100 °C regarding both performance and design parameters. It is comparable with the zeotropic ORC, while traditional ORC is the best choice for higher heat source temperatures.

Absorption Power Cycles (APCs) provide an interesting field within power cycles. The multicomponent mixture with variable temperature across boiling is employed as a working fluid. This has a potential for decreasing exergy loss associated with heat transfer during phase change processes (boiling and condensation). Absorption process has also an effect of lowering exhaust pressure of a turbine. The APCs hold a potential for heat recovery applications at very low temperatures, where constant temperature of boiling and condensation largely limits performance and economic effectiveness of Organic Rankine cycles (ORCs). Theoretical calculations show superiority of APC over extensive range of considered ORC working fluid. The advantage of APC further increases when air cooled condenser needs to be used instead of wet cooling tower. With the same boundary conditions for all cycles the APC provides higher utilization efficiency and power output at source temperatures below approximately 120 °C, for temperatures as low as 60 °C the net power output can be surpassed even more than three times. The proposed APC employs aqueous solution of salts considered generally for absorption cooling (Lithium Bromide, Lithium Chloride, Calcium Chloride) as a working fluid. Unlike ammonia used in mixture with water in Kalina APC or often ORC working fluids, used salts are non-toxic, environmentally friendly and pure water in expander simplifies its design. After summary of theoretical research from thermodynamics point of view are discussed principles, aspects and issues for design of single components of the cycle. Results of sizing are presented on two examples with 100 °C heat source. First one is 20 kWe unit using hot air as a heat source and air cooled condenser, second one is 500 kWe unit with heat source being pressurized water and using wet cooling tower heat rejection. Results show possibility of building relatively efficient system for even small power output with turbine isentropic efficiency nearly 80 % for the 20 kWe unit, but relatively large heat exchangers.

This paper describes some results obtained by the study of influences of different factors which define reliability of solder joints. Generally, these factors include substrate, type of solder paste, soldered components, surface protection of soldering areas and methods of reflowing. In our case, these influences are evaluated with focus on PCB with OSP surface protection under condition of thermal cycling and shear testing. The results from experimental measuring are complemented with computer analysis of models of solder joints and components in ANSYS. Finally, there is evaluation of practical results in conjunction with simulations.