Martin Pavlas

Heat integrated heat pumping for biomass gasification processing

Abstract The main part of this paper is an industrial case study. It deals with an application of a heat pump in energy systems for biomass gasification in a wood processing plant. Process integration methodology is applied to deal with complex design interactions as many streams requiring heating and cooling are involved in the energy recovery. A refrigeration cycle maintains low temperature in the scrubber where the production gas (or synthesis gas–syngas) is cooled and undesirable contaminants are removed before the syngas is introduced into the engine. In addition to electricity generation, a large amount of waste heat is available in the biomass gasification system studied in the paper, and its appropriate heat integration with utility systems within a plant allows the available heat to be efficiently utilized for the site. The conceptual understanding gained from the case study provides systematic design guidelines for further process development and industrial implementation in practice.

Using a utility system grey-box model as a support tool for progressive energy management and automation of buildings

Abstract The research presented here is focused on improving energy management in a building complex through analytical and empirical modelling of its utilities. First, we introduce current European policy on energy savings in buildings. The modelling starts with a literature review and a thorough study on a heating and cooling system of a particular building complex—the National Theatre in Prague, Czech Republic. Standard building automation and control systems cannot optimize the building’s operations to the fullest and thus do not provide the best cost savings possible. A mathematical model of the energy system and its integration into a building control system is an essential prerequisite for any optimization here. The development of a model which can be integrated into a control system during real-time operation of the building is a very complicated task. Our paper presents a procedure to develop such a model and methods to apply it in a real-life operation. First, the mathematical model is implemented in a simulation tool, which enables an efficiency evaluation of the system. This simulation tool offers especially important support for building automation and control systems when deciding the most effective operation of heat or cold utilities. The model greatly helps in monitoring and optimizing daily offtake limits for natural gas, which is highly appreciated by the building’s technical management. Our practical applications of the model show new possibilities for simulation and optimization calculations which are completely unique in building management systems so far.

Improving the Energy Management of a Building Complex through Utility System Modelling

Abstract According to Escriva-Escriva (2011), utility systems are often managed by non-specialised technicians who need understandable and cost-effective actions to be implemented. Therefore, we can assume that tools for simulation and optimization may further improve operation of utility systems. However, a good model is essential for these purposes. The paper deals with complex utility system modelling using operational data. Our experience shows that data acquisition in common utility system of a municipal building is sometimes poor. Usability of a model based on data of lower quality is discussed and demonstrated on the case of the utility system of The National Theatre building complex in Prague, the capital of the Czech Republic. It shows that even model based on poor data may be useful for some energy management improvements.

Impact assessment of pollutants from waste-related operations as a feature of holistic logistic tool

Waste management has still been a developing and progressing field, which demands continual improvements in waste transportation as well as proper selection of locations and technical operation of new treatment facilities. Most of research papers on waste management planning have been dealing with optimisation of network flows, thus minimising the cost and improving economic criteria. The shortest paths to treatment facilities are considered together with detailed analysis of their operation including heat and electricity demands in their vicinity. The tasks sometimes include social and global environmental criterions, however, the direct local consequences also play an important role and should be examined. A decision-making strategy in waste management updated with the local emission impact on the population is proposed in this paper. The paper focuses on the first move in analysing the production, dispersion, and impact of pollutants, originating in transport, with regards to the population living close to routes. The calculation of emission produced during the transport of waste takes into consideration the altitude profiles of routes, container loads, and specific types of vehicles. The consecutive estimated impact on the population reckons with the distances between routes and municipalities as well as their sizes in terms of the numbers of inhabitants, where the transportation routes are divided into smaller segments and dispersion is limited with threshold value. The proposed approach describing the emission effect has been tested using real-life operating data corresponding to the specific, 81 km long route along which approximately 25 t of waste is transported 800 times a year. The impact of pollutants on the population was evaluated and discussed. Results of the analysis were quantified for this route to create an edge characterisation needed for further calculations. This approach applied to the whole network then yields input data needed for future research of novel strategies in facility location problems. Other possible extensions of the presented approach include more accurate dispersion function or detailed calculation of the impact of pollutants with respect to specific locations of residential houses.

Waste processing facility location problem by stochastic programming: Models and solutions

The paper deals with the so-called waste processing facility location problem (FLP), which asks for establishing a set of operational waste processing units, optimal against the total expected cost. We minimize the waste management (WM) expenditure of the waste producers, which is derived from the related waste processing, transportation, and investment costs. We use a stochastic programming approach in recognition of the inherent uncertainties in this area. Two relevant models are presented and discussed in the paper. Initially, we extend the common transportation network flow model with on-and-off waste-processing capacities in selected nodes, representing the facility location. Subsequently, we model the randomly-varying production of waste by a scenario-based two-stage stochastic integer linear program. Finally, we employ selected pricing ideas from revenue management to model the behavior of the waste producers, who we assume to be environmentally friendly. The modeling ideas are illustrated on an example of limited size solved in GAMS. Computations on larger instances were realized with traditional and heuristic algorithms, implemented within MATLAB.

Material analysis of Bottom ash from waste-to-energy plants

Bottom ash (BA) from waste-to-energy (WtE) plants contains valuable components, particularly ferrous (Fe) and non-ferrous (NFe) metals, which can be recovered. To assess the resource recovery potential of BA in the Czech Republic, it was necessary to obtain its detailed material composition. This paper presents the material composition of BA samples from all three Czech WtE plants. It was found that the BA contained 9.2-22.7% glass, 1.8-5.1% ceramics and porcelain, 0.2-1.0% unburnt organic matter, 10.2-16.3% magnetic fraction, 6.1-11.0% Fe scrap, and 1.3-2.8% NFe metals (in dry matter). The contents of individual components were also studied with respect to the BA granulometry and character of the WtE waste collection area.