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Lichota J.,Instytucie Techniki Cieplnej i Mechaniki Plynow | Lepszy M.,Instytucie Inzynierii Lotniczej
Rynek Energii | Year: 2013

This article shows the results of experiments that allow for the identification of dynamic properties of balls filled with phase change material (PCM) changing its physical state from solid to liquid during the delivery of heat. PCM behaviour was studied using impulse signal through changing the temperature of the water, which surrounds PCM. The impulse response of heat accumulator was modeled utilizing transfer functions of first order differential equations. The resulting theoretical model was compared with measurements. Equations of the single ball allow the modeling of dynamic properties of heat accumulator during charging and discharging. This is important during operation of CHP supplying district heating where prediction algorithms are applied. Knowing a future heat demand by customers and knowing the characteristics of the accumulator, CHP can more precisely set an electricity selling policy on a market.

Wojs K.,Instytucie Techniki Cieplnej i Mechaniki Plynow | Lichota J.,Instytucie Inzynierii Lotniczej | Bechtold Z.,Instytucie Techniki Cieplnej i Mechaniki Plynow
Rynek Energii | Year: 2011

This paper presents methodology of thermal computations for heat storage in phase changing materials (PCM). Computational and experimental results are shown for paraffin. Several concepts of applications of PCM in power stations and CHP's are discussed.

This paper describes changes in domestic heating networks till 2025 on example of Wrocław and Opole. Conclusions concerning directions of heat market development are drawn from changes in international environment, then national, and the specificity of both cities. The authors predict that the implementation of EU law in Poland will lead to considerable transformations in the market and heat sources leading to reduction of heat demand by customers and increasing optimization of heating systems.

Pawlak-Kruczek H.,Instytut Techniki Cieplnej i Mechaniki Plynow | Lichota J.,Instytucie Inzynierii Lotniczej | Plutecki Z.,Instytucie Elektrowni i Systemow Pomiarowych
Rynek Energii | Year: 2011

This paper shows the results of research performed on own constructions of a brown coal dryer. Three different constructions of dryers were considered and investigated. Energy demand for commercial dryers depends on utilized process and is in a range (330, 4000) kJ/kg H2O. The authors showed energy demand for own constructions; coal analysis: water content before and after drying, chns - analysis, TGA analysis. Simulations of a drying process inside a dryer are shown, too.

Wojs K.,Instytucie Techniki Cieplnej i Mechaniki | Polko K.,Instytucie Inzynierii Lotniczej | Lichota J.,Instytucie Techniki Cieplnej i Mechaniki
Rynek Energii | Year: 2012

The paper shows methodology of computation of condensing cross-flow, counter-flow heat exchanger flue gases-water utilized to heat recovery from flue gases leaving lignite fired power station. The method of computations is presented on example of design of heat exchanger area A recovering heat from flue gases. At the beginning computations were performed for heat transfer without condensation, then after reaching dew temperature through flue gases - with condensation. All operational parameters were set along length of the condensing heat exchanger.

Lichota J.,Instytucie Inzynierii Lotniczej
Rynek Energii | Year: 2010

This paper presents inverse model control loop characterized of utilization the same set of process data to obtain control structure with ideal transfer functions Gz(s), GU(s). In case of disturbances Z(s) output signal Y(s) doesn't change GZ(s) = Ym(s)/Z(s) = 0. In case of set-point value change output value Y(s) changes immediately GU(s) = Ym(s)/Yz(s) = 1. Proposed control loop structure is shown in Fig. 3. Two different mathematical proofs for LTI processes - utilizing block diagrams and analytical - are presented (points 2.1, 2.2). Generalization for nonlinear processes is proposed. Instead of linear process and inverse process model in control loop an artificial neural network is used. Three examples of control loop application are shown (3.1, 3.2, 3.3). Extensive researches on this type of control loop show that it can be used for nonlinear unstable processes.

Lichota J.,Instytucie Inzynierii Lotniczej | Chorowski M.,Instytucie Inzynierii Lotniczej
Rynek Energii | Year: 2014

A paper describes the principles, which should be utilized to design tri-generation. A consequences of non-compliance with the rules were shown.

Lichota J.,Instytucie Inzynierii Lotniczej | Grabowski B.,Instytucie Inzynierii Lotniczej
Rynek Energii | Year: 2011

This paper shows examples of utilization of algorithm designed for hydraulic computations presented in part I under same title [9]. Examples are important for modeling of different applications in district heating like increase of pipe resistance (point 1.2), damage of pipe (point 1.3), damage of heat node (point 1.4), a new pump location in a network (point 1.5), non-equlibrium of water mass flow from source and at customers (point 1.6), a new heat source location in network (point 1.7) and reduction of mass flow from existing source (point 1.8). Example 1.1 describes assumed basic geometry of network and proposed algorithm of initial mass flow computing. Setting initial mass flow is not trivial problem because number of equations are less than number of variables. The only condition, which should be meet to obtain mass flows in network from non-linear algebraic set of equations is such, that initial mass flow have to fulfill that set. In contradiction to Moore-Pennrose solving a problem by giving as an answer "best" result in sense of least squares proposed algorithm is very simple and requires less computations.

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