Sep 16, 2013 - Alternative configurations of absorption heat transformer are ... Regarding the quantity of distilled water rate, an optimization is performed.
monitor all useful data of distribution transformers to reduce costs. (5) Many monitoring systems .... Nameplate rating of Distribution Transformer: KVA rating: 500.
indicates the outage time for each branch section when there are faults on the other branch sections. Outage time could be either repair time or isolation time depending on different fault locations, topology and configuration of the feeder and prote
May 22, 1998 - Abstract. The failure of a large power transformer is an area of significant concern since it can result in millions of dollars in costs as well as a possible interruption of power. Therefore, it is desirable to detect the existence of
KeywordsâWavelet, Power Transformer, EMTP, Circuit. Breaker, Monitoring .... if this kind of swing begins to develop, the monitoring system as to send an alarm signals to ....  RST Ltd, Transanal-16 user's manual, Budapest, 2001.  G.B. ...
Dec 2, 2008 - Now, a current transformer can saturate due to following two reasons: 1. Large AC currents and CT burden. 2. DC offset current. Condition 1 is related to the improper selection or usage of. CT circuit. It can be taken care of during des
for the primary circuit of transformer and 2. U , 2. I , 2. Z ... be equivalent whit 1. U and, other .... power up the three autotransformers which supply each phase of ...
May 5, 2013 - Abstractâ A distributed transformer networks remote monitoring system(DTRMS) is developed and constructed, for monitor and record the parameters like temperature, oil level status, of a distribution transformer. The system consists of
I would like to express my earnest gratitude and regards to my project guide, Professor. Susmita Das, Department ... This project is about design and implementation of a mobile embedded system to monitor and record key ... (5) Many monitoring systems
number of gases compounds such as H2, O2, N2, CO, CO2, CH4,. C2H6, C2H4, C2H2 and C2H8. These gases are further analyzed to investigate presence of ...
transforms a system of alternating voltages and current into another system of alternating voltages ... Monitoring the performance of a transformer is crucial in.
Mar 1, 2015 - temperature monitoring methods are electrical signal measurement and infrared ... Such as thermocouple and resistance thermometer sensor, etc. ...... and S.K.Pal, "Temperature Analysis of Induction Motors Using a.
Feb 26, 2016 - cient (convection coefficient) determined by the Newton's law of cooling. Conduction is the dominant heat transfer mechanism in loaded bushings. So, the electrical equivalent circuit analysis suits it. Heat conduction occurs in the inn
Index Terms â Power transformer, embedded systems, transformer protection. I. INTRODUCTION. Power transformers are the important part of power system which are used to step up and down the power to make usable for electricity consumers. Transformer
an increasing interest in applying monitoring systems and on line diagnosis methods to ... transformer oil-tank vibration, but without measuring the current ...
The trouble with many transformer monitoring systems is that they are not able to control or make decisions and recommendations based on the avail- able data ...
Abstract--This paper presents a new distribution trans- former monitoring system (DTMS), called Wimo, which util- izes the existing communication network, has ...
Jul 26, 2004 - For this reason, maintenance crews would periodically take transformers and circuit breakers off-line ... diagnostic system that can be used to monitor the health of the transformer and other substation equipment. ...... For protection
Jul 31, 2012 - transformer. Through-fault currents create forces within the trans- former that can eventually weaken the winding integrity. A com- prehensive transformer protection scheme needs to include pro- tection against transformer overload, th
technique. Two 13.8kV-231V, 500 kVA transformers were ... 1 cm, a) Two laminations per layer, b) Eight laminations per layer. 4) Magnetic ...  ANCE, NORMA NMX-J-116-1996-ANCE, Transformadores de ... in 1990 and 2000, respectively.
tool that uses vector analysis to evaluate process hot and cold streams and to ... heater, and a water pump with adjustable volume flow rate. ... A non-toxic, non-flammable, environmentally safe working fluid for high-temperature applications.
Mar 1, 2015 - Keywords: inrush current, internal fault, MATLAB, power transformer, wavelet transform. Copyright ... The wavelet transform for analysing the transient phenomena in a power .... an application to power transformer protection.
differ, this study used the standard data of IEC, IEEE, and CIGRE as condition .....  IEEE Standards IEC60599, IEEE Guide for the Interpretation of Gases.
Experimental heat transformer monitoring based on linear modelling and statistical control process A.M. Hdz e Jasso a, M.R. Contreras e Valenzuela b, c, A. Rodríguez e Martínez b, R.J. Romero b, *, M. Venegas d a
Engineering and Applied Science Postgraduate School, Autonomous University of the State of Morelos, Av. Universidad 1001, 62209 Cuernavaca, Mor., Mexico Research Centre for Engineering and Applied Science, Autonomous University of the State of Morelos, Av. Universidad 1001, 62209 Cuernavaca, Mor., Mexico c Chemistry and Engineering College, Autonomous University of the State of Morelos, Av. Universidad 1001, 62209 Cuernavaca, Mor., Mexico d Departamento de Ingeniería T ermica y de Fluidos, Universidad Carlos III de Madrid, Av. Universidad 30, 28911 Legan es, Madrid, Spain b
h i g h l i g h t s
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This paper proposes a new way to monitoring absorption heat transformer components. Potential and actual capacity values indicate an AHT capable process. Waste heat at evaporator makes the recover absorber temperatures tend to 92.8 C. Condensation process was under statistic control at 24.7 C in normal distribution. Analysed steady state shows variations lower than 2% in each temperature component.
a r t i c l e i n f o
a b s t r a c t
Article history: Received 7 November 2013 Received in revised form 29 August 2014 Accepted 6 September 2014 Available online 16 September 2014
A.M. Hdz e Jasso et al. / Applied Thermal Engineering 75 (2015) 1271e1286
1. Introduction Absorption heat transformers (AHT) are thermo e mechanical devices in which the main feature is the recovery of waste heat. AHTs are capable of recovering a large amount of energy and increase its temperature, using part of the same energy as power in a thermodynamic cycle. The increased temperature inside any closed thermodynamic system is a consequence of the increment of pressure. The difference of pressure in an AHT is obtained by means of a relatively small (2%) amount of mechanical energy supplied by a mechanical pump to move a ﬂuid; it is a measured value for this AHT  for the pumps consumptions of 32 W each. One of the most important challenges of the AHT technology is the cycle control. AHT devices are affected by environmental conditions (rain or wind) because one of their components interacts with the environment. There are 60 variables interacting in an AHT in order to achieve the desired effect, i.e., revaluing waste energy. The parameters present in an AHT are Temperature, Absorbent Concentration, Pressure, and Flow. There are two main thermodynamic parameters in the operation of an AHT: the ﬁrst is the relative recovered amount of energy that is recovered, shown in the Coefﬁcient of Performance (COP) and second the absolute increase of temperature in relation to waste energy (GTL).
remains in the bottom of the generator, which is sent to the absorber by means of a micro-pump. The steam created in the generator is sent to a component that is called condenser. In the condenser, the steam exchanges heat with a stream of cold water that is not useful, as its temperature is near the room temperature. Once the steam heat is exchanged, water in liquid phase is sent to the evaporator by means of a second micro-pump. In the evaporator, the exchanged waste energy turns into steam again, but at a relative high pressure. The evaporator drives the steam through a pipe to the absorber. In the absorber, the solution of concentrated aqueous Carrol gets into contact with high-pressure steam, causing high temperature absorption. This heat is the useful heat in the AHT. The solution formed is the diluted aqueous Carrol and is sent to the generator through a pipe. The entire cycle can be seen in Fig. 1. The operating conditions are reported on Table 1 to operate the AHT. The generator, evaporator and absorber are Plate Heat Exchanger and have 7 corrugated plates and 3 channels per pass. The condenser has 4 corrugated plates and 1 channel per pass for working ﬂuid (water) and 2 channels per pass for cooling ﬂuid. The total operating design AHT power is 10 kW at Table 1 operating conditions.
4. AHT's options for control 2. Analyzed parameters There are two important parameters for the industrial processes: quantity and quality. In the case of recovery of industrial waste heat, quantity is given by the recovered power (calculated by COP), and quality is given by the thermal level of recovery (calculated by GTL). In this paper, the Coefﬁcient of Performance (COP) parameters are deﬁned as the relationship between the thermal energy that is recovered and the total inlet of thermal energy. This deﬁnition ignores the performance of mechanical pumps, in which are two orders of magnitude lower .
QAB QGE þ QEV
The absolute increase of temperature is deﬁned as the difference between the temperature of the absorbent and the temperature of the evaporator.
GTL ¼ TAB TEV
In an AHT, the variables that drive great changes in the two parameters deﬁned in the section above are Temperatures, since the changes in Pressure and Concentration do not affect the AHT performance considerably. 3. AHT cycle The AHT has four basic components: two for energy inlet, and two for heat rejection. The inlet components are the generator and the evaporator. The rejection components are the absorber and the condenser. There is an internal heat recirculation that increases the recovery of waste heat; it is called economizer . The thermodynamic cycle under study starts with a waste heat exchange towards two AHT components simultaneously. There is an exchange of energy with the generator that contains a mixture called aqueous Carrol. The mixture Water/Carrol developed by Carrier Corporation. Carrol is an aqueous LiBr mixture with a crystallization inhibitor (ethylene glycol) in the ratio 1:4.5 by weight . Inside the generator, the water evaporates and is conducted to the upper part, due to density difference. A concentrated solution of aqueous Carrol
Statistical process control is a widely used methodology in manufacturing and services; it allows monitoring, controlling and improving the quality of a process [2,12,20,22]. However, it has not been applied in AHT at all. This methodology may provide an option for improving the monitoring of the process. A recent review , shows that there are two options on improvement for heat pumps that are based on lithium bromide: the use of inhibitors, and mechanical designs. On the other hand, in control systems for compression heat pumps, progress has been made in dynamic control based on storage  and there is a proposal for the increase of COP based on a control strategy, by means of plate exchangers . A method proposed by Liao & Radermacher  consists basically of increasing the set point of the Chiller temperature to prevent the risk of crystallization. Recently, in addition , the control of high temperature for the recovery of industrial waste heat has been considered as a challenge. However, in the case of AHT there is only one study, based on the Statistic Process Control , which conducted a comparison between two designs. Other studies that refer to some type of control in AHT  suggest that maintaining the ﬂow relationship constant is a control strategy; however, the study belongs to exergy and not to control. One correspondent and his team  reported an AHT for water puriﬁcation in which testing showed control problems; in a similar manner, the correspondent and his team  had previously reported an AHT control based on pumps with adjustable gears and electric resistors for a study on exergy under steady conditions. There is an opportunity to improve the quality by statistical analysis in heat transforming process  based on function regression. In this paper temperature is the independent variable for capability evaluation, similar to the new methodologies for energy loads in buildings .
5. Control by linear approximation model In the case of AHT, in steady state, a COP value for each GTL value is expected as function of TAB for a constant TEV. These values may be correlated, assuming a model based on the following equation: