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Milewski J.,Wydziale Mechanicznym Energetyki | Badyda K.,Politechnice Warszawskiej | Wolowicz M.,Wydziale Mechanicznym Energetyki
Rynek Energii | Year: 2010

The paper presents a 30 kW micro Combined Heat and Power (μ-CHP) system which is able to provide heat and power for a more efficient energy use in a hotel. The main objective of μ-CHP unit is to introduce the novel concept of a Polymeric Electrolyte Membrane Fuel Cell based CHP (μ-CHP-PEMFC) system able to satisfy both the thermal (heating and sanitary water), cooling and electrical power need of the whole building replacing the small methane boiler installed in the single flats as well as old-fashioned centralised oil thermal plant. To address current limitations in hydrogen supply the system is equipped with a compact steam reforming unit able to produce a hydrogen rich mixture suitable for feeding PEMFC starting from methane, methanol or bio-gas without any modification thanks to several innovative concepts based to very reliable and efficient catalysts as well as related design and manufacturing process. Adequate control unit quantify the amount of energy flowing in (electrical/thermal energy consumption) and flowing out (excess of electrical power sold out) from the μ-CHP-PEMFC. The 30kWeli proposed size is the results of a market study which based on the assumption that the average power need for an apartment is about 1kW and therefore the proposed size is suitable to provide electrical power to the hotel with at least 20-25 apartments; moreover the required emergency power of the hotel can be covered by the proposed unit during any black down of the external electric network. As far as the heating need is concerned, the CHP system provides about 50kW th of additional heat and a small condensation boiler fills up the exceeding thermal need when required. The functioning principle of the CHP system with fuel cells is described.

Badyda K.,Zakladzie Maszyn i Urzadzen | Kupecki J.,Politechnice Warszawskiej | Milewski J.,Wydziale Mechanicznym Energetyk
Rynek Energii | Year: 2010

Paper presents the results of the novel numerical modelling tool created in HYSYS code, capable of optimizing hybrid power cycles based on a coal gasification. Software allowed creating robust model of a system in which generated through coal gasification syngas supplied high temperature fuel cell, namely SOFC. The developed tool allows determining the optimal design point as well to perform sensitivity analysis in order to investigate overall system efficiency change in respect to parameters changes. Authors pinpointed advantages and disadvantages of the proposed system and suggested possible improvements in the numerical tool development. Analyzed system represents clean energy sources and allows for reduction of the environmental burdens associated with electrical power generation. Presented work has been conducted in Institute of Heat Engineering, Warsaw University of Technology in cooperation with Fuel Cell Center, Colorado School of Mines, USA.

Milewski J.,Wykladowca na Wydziale Mechanicznym Energetyki | Badyda K.,Politechnice Warszawskiej | Miller A.,Warsaw University of Technology
Rynek Energii | Year: 2010

The advanced mathematical model of Solid Oxide Fuel Cell (SOFC) is presented. The governing equations of the model are presented and described. Based on the model the influence of fuel composition on SOFC performance is shown. Hydrogen is used as reference fuel.

Milewski J.,Warsaw University of Technology | Wolowicz M.,Wydzialc Mechanicznvm Energetyki | Badyda K.,Politechnice Warszawskiej | Misztal Z.,Warsaw University of Technology
Rynek Energii | Year: 2011

The paper presents operational characteristics of start-up and shut-down of a 30kW micro Combined Heat and Power (μ-CHP) system. The main objective of the μ-CHP unit is to introduce the novel concept of a Polymeric Electrolyte Membrane Fuel Cell based CHP (μ-CHP-PEMFC) system able to supply heating (heating and sanitary water), cooling and electricity. Whereas the plant description was provided in the previous paper (Rynek Energii 5(90) 2010), the objectives of this paper are the main aspects of the start-up and shut-down procedures which were performed in situ. The plant is composed of three main units: reformer, CO oxidizer (reactor "water gas shift" and oxidation reactor - "prox"), and PEMFC. The sequence of the start-up procedure is as follows: heating up the reformer and CO oxidizer to a temperature of 700-800°C. A double-fuel burner is used to heat up the reformer. Then composition of the gas leaving the reformer is then checked. The outlet gas from the first part of the reformer (called syngas) contains about 5% CO, which is destructive for fuel cells such as PEM. The maximum acceptable level of CO in fuel for this category of fuel cell is approximately 25ppm. In the second part of the reformer, CO is reduced in catalytic reactions. This is the most difficult and time-consuming process due to the high sensitivity and inertia of the whole cycle. After adjusting some parameters, much time is needed to stabilize the process and check the results of the changes. After achieving the required CO levels in syngas, the control valve can be opened to feed the fuel cell and start production of combined heat and power.

Deszczynski B.,Instytucie Techniki Cieplnej Politechniki Warszawskiej | Swirski K.,Kierownik Zakladu Maszyn | Badyda K.,Politechnice Warszawskiej
Rynek Energii | Year: 2010

This paper describes an innovative computer system used to optimize work of CHP plant with a heat accumulator. Municipal heat networks are more often being equipped with large heat accumulators. Application of the designed system allows maximizing the benefits of optimal use of the tank, such as offsetting the burden and maximizing profits from the production of electricity and heat. Analysis of benefits from using a heat tank was dependant on a CHP model with a heat accumulator. The model proposed a division of the heat tank into layers with a constant water temperature. Moreover the article illustrates the process of using core system components, key elements architecture and the way the outcome of the solution is presented to the end user.

Reflections concerning, using mathematical modelling, performance of selected systems with gas turbines are presented in this paper. These issues discussed in the literature, are often associated with other solutions than the gas-steam cycles such concepts including Combined Cycle in more complex plants with gas turbines. These are, for example: recuperation (regenerative heat) cycle, Brayton-Brayton cycle, Brayton-Diesel cycle and many others considered, often only mentioned in the literature.

This paper presents considerations relating to the problems of the parameter selection of the combined steam and gas cycle with heat recovery steam generator (Combined Cycle). On the basis of the characteristics developed, main conditions associated the determination of parameters of the single pressure steam part are pointed, including the impact of supplementary firing. Selected results of the analysis for characteristic configurations of two-pressure and three pressure systems are presented. Selected parameters and characterized of recently offered combined steam and gas plants are assembled and characterized.

The article presents analysis on the changes in the performance of gas turbine district heating power plan with waste heat water boiler due to the replacement of combined cycle gas and steam unit. Analysis was performed for the installation of electrical power output about 20 MW, consisting of two gas turbines. The calculation results are presented in the form of graphs-for selected configurations of steam part in the single-pressure arrangement. It was a lay-out with backpressure and extraction-condensing steam turbine considered. The impact of the introduction of waste heat water heater in the boiler on the performance of the system was taken into account.

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