Heat Meter Research Articles

Uncertainty of the Calibration of Paired Temperature Sensors for Heat Meters

In heat meters, the temperatures of the incoming and the outgoing water are measured with calibrated platinum resistance thermometers. They are subject to legal metrology and the requirements for the uncertainty associated with the temperature difference are specified in national and regional standards. It is difficult to calculate this uncertainty, since it depends on the characteristics of both sensors and correlation needs to be considered. Causes of that correlation include calibration in the same facility, losses due to heat conduction, and common electrical measurements. Therefore, an analytical calculation of the temperature difference and the associated uncertainty is quite complicated, requiring several steps, corrections, and approximations. Monte Carlo techniques avoid these difficulties by simulating the calibration of both sensors simultaneously. As expected, the correlation reduces the uncertainty associated with the temperature difference indicated by the sensor pair considerably. Monte Carlo simulation and analytical calculations are briefly described and their results are compared.

Field investigation on consumer behavior and hydraulic performance of a district heating system in Tianjin, China

With the implementation of heat reforms in China, the application of thermostatic radiator valves (TRVs) has been gaining popularity in the new-style district heating systems (DHSs). The objective of this study was to investigate consumer behavior (including regulation of TRVs and opening of windows) and its influences on the hydraulic performance and energy consumption of individuals and the whole system. The concurrence rate of individual behaviors and hydraulic interactions between individuals were analyzed. This study should be helpful to gain a comprehensive understanding of the new DHSs in China and consider a proper design/control strategy for these systems. Questionnaires and field observations of consumer behavior, tests of hydraulic performance, and surveys of energy consumption were carried out in a DHS in Tianjin, which was one of the heat metering and billing demonstration projects in China. The main results of the tests were as follows: water flow performance in apartment-level heating systems were diverse because consumers’ behavior was varied and unpredictable, and the hydraulic interaction between consumers living along the line of a vertical pipe was obvious, and was stronger for terminal consumers with their TRVs set to higher values; however, flow variations in the whole DHS, which included 910 households, were relatively constant. A probability analysis was carried out to explain this phenomenon, and the conclusion was drawn that when there were more than 200 consumers, the stochastic consumer regulation behavior would bring less than 10% of total flow variations. Finally, the power consumption of the circulation pump, heat consumption and energy-saving potential of this type of DHS were discussed and some suggestions for TRV regulation and pump operation were made.

Fluid Characteristics of Rotary Wing Heat Meter With Single-Channel

Fluid characteristics of a rotary wing heat meter with single-channel were studied through theretical analysis, numerical simulation and experiments. The obtained results show that the number of vanes can obviously influence the heat meter, but the water temperature seldom influence the meter, and the optimal number of vane is 6-8.

Testing of Data Processing Software in Heat Metering Systems

Nowadays measurement system parameters and characteristics basically depend on microprocessors and their software. Hence, verification of measurement systems software (MSS) is very important. After adoption of the Measurement Instruments Directive (MID), verification of MSS will be necessary. For investigation of heat metering systems metrological reliability testing methodology was created. Experimental stand and mathematical model were build. Experimental testing results of temperature measurement software are presented. Ill. 6, bibl. 8 (in English; summaries in English, Russian and Lithuanian).

A method for heating consumption assessment in existing buildings: A field survey concerning 120 Italian schools

A field survey was carried out in order to collect, elaborate and analyse data concerning the actual energy consumption for space heating of a sample of about 140 buildings (120 high schools) in the Province of Torino (Italy). The buildings were equipped with heat meters. For each building the primary energy consumption (i.e. the fuel consumption multiplied by its net heat value), the metered supplied thermal energy, the daily and seasonal operating periods and the climatic data of the site were monitored. The energy consumption data, both annual and monthly, were normalised and statistically analysed in order to compare different buildings and different heating seasons. The study aimed at evaluating a “specific energy performance indicator related to space heating” for each building. This indicator may be used to establish benchmark values in heat energy service contracts, to predict heat energy consumption or to verify the increasing/decreasing of the actual consumptions in future heating seasons with respect to the benchmark value. Moreover, this is very useful to find out those buildings not complying energy requirements and, as a consequence, requiring a deeper energy diagnosis. The study is part of a research project between Politecnico di Torino and Provincia di Torino, stimulated by the Directive 2002/91/EC on building energy performance, focused on evaluating the energy performance of existing buildings.

EQUIPMENT BASED CONTROL SYSTEM STRUCTURES FOR COMPLEX AND INTEGRATED SYSTEMS INTENTION AND INDUSTRIAL APPLICATION EXAMPLE

The article describes the approach and the implementation of an equipment based control strategy. Based on a view of subsystems in a production, process or a single machine the control system has to abstract the subunits in an object orientated manner on their methods and properties. The base subunits will run as separated state machines (either on centralized or decentralized control devices) representing themselves to the next control hierarchy level only by said methods and properties. These base subunits form functional subsystems in the same way.Advantages are easy replacement of different base units with the same functionality to the next hierarchy level, high efficiency in construction kit engineering of systems, easy integration of systems to vertical integration attempts – especially in the field of networking and data concentration.The challenge is the implementation on standard industrial PLC systems with a standard industrial EN 61131 like programming language.The example demonstrates the implementation in the most modern test stand for heat meters for the famous German PTB institute, a system with about 1000 physical I/O and measurement points.

An investigation of the balance method of measuring unsteady heat flux

A method of measuring unsteady heat flow, based on the balance equation of heat flows at the entrance and inside the object, is described. The theoretical principles for obtaining formulas and results of investigations on a thermal model are presented. Diagrams of a heat meter and of a measuring system are given.

RESREARCH ON FLUID CHARACTERISTIC WITHIN THE ROTATING-WING HEAT METER *

In order to improve the performance of rotating-wing heat meter and reduce the cost of development, the three dimensions numerical calculations of the internal fluid characteristic within a heat meter are carried out based on the standard k-e turbulent mode, the finite volume method and SIMPLE algorithm. The speed field and pressure distribution within heat meter are analyzed according to the result of numerical calculation. The flux measurement accuracy and pressure loss of basal meter are forecasted according to the calculated results. The calculated results of the impeller’s rotating speed are compared with experimental results and prove the validity of the calculated results. This researches shows the calculated results can forecast the performance parameters of basal meter and can provide great help for design of the heat meter.

The influence of installation conditions of heat meters on interior fluid field and flux mearsurement accuracy

Abstract The installation condition of heat meters has an influence on interior fluid field and flux measurement accuracy. In this paper, this influence is investigated through experimental research and numerical simulation. The results indicate that the influence of the length of tubes in front of heat meters can be neglected when L≥4D (L is the length of tubes in front of heat meter, D is the diameter of heat meter). This conclusion has been of great value on academic theory and practical application.

Parametric identification of unsteady heat fluxes using thin-disc heat meters

A unified procedure for measuring unsteady heat fluxes based on one-dimensional receivers is proposed. A digital Kalman filter algorithm is used to obtain optimum estimates. The results of investigations of heat meters, the operating principle of which is based on the thin-disc method, are presented.

The influence of installation conditions of heat meters on interior fluid field and flux measurement accuracy

The influence of installation conditions of heat meters on interior fluid field and flux measurement accuracy

Diagnostics of Metrological Defects in Heat Metering Problems

Diagnostics of metrological defects arising when the measured parameter exceeds the upper limit of the dynamic measurement range of heat meters in a closed-loop heating system is studied.

A Modernized Calorimeter for Measuring the Isobaric Heat Capacity of Hydrocarbons by a Continuous-Flow Method in the Critical Region

A method is described for the precision measurements of the isobaric heat capacity Cp of hydrocarbons of the normal series in a wide neighborhood of the critical point, characterized by anomalously high values of Cp, the presence of maxima and high temperatures, for which thermal decomposition of the products investigated is possible. Modernization of the method was undertaken in order to increase the accuracy of measurements of the absolute temperatures (the reference temperatures) and small differences in temperature (ΔT < 0.1 K) with original “ignoble” thermocouples. In order to minimize heat loss in the calorimeter and to increase the reliability of the experimental equipment, a new construction of the heat meter was developed and a metrological estimate of it was carried out.

Heat Metering in Water-Based Heat Supply Systems

Commercial heat energy metering is considered, particularly the details of Russian water-based heat supply systems, with emphasis on minimizing the metering costs.

Distributed measurement system for heat metering and control

Measuring and charging heat consumption are not often worked out in the prevalent warm-water heating systems. The developed modern heat-meter device, which includes a microcontroller, is self-calibrating and self-testing; it uses several correctional algorithms in order to increase accuracy after authentication. Consumption data and information about the work-state events are logged and stored by the measuring unit. The discrete devices are connected to a local concentrator via M-bus. The concentrator is connected to the central supervisory system through a mobile communication channel. In this system, the meter devices respond to arising failures. The center collects information about measuring and usage. This solution highly increases the efficiency and the reliability of the system.

고강도 콘크리트의 수화열 저감에 미치는 혼화재 종류 및 대체율의 영향에 관한 연구

The hydration of cement paste occurs when the cement is miked with water. During the hydration, hydration heat causes the thermal stress depending on the site of concrete and the cement content. Especially in the high-strength concrete, we must give care to the concrete due to its large cement content. In this study conduction calorimeter and concrete insulation hydration heat meter were used to investigation the hydration heat characteristics of cement and concrete. To reduce hydration heat of high-strength concrete, several types of replacement of fly-ash and blast-furnace slag powder were used in this experiment. As a result of this study, it was found that hydration heat of high-strength concrete was reduced by replacement of fly-ash and blast-furnace slag powder. In case of high-strength concrete using blast-furnace slag powder, the max-heat arrival time was delayed but an effect of heat reduction was lower than a case of high-strength concrete using fly-ash, because it was considered that the heat-dependence property of blast-furnace slag powder was higher than that of fly-ash.

Metrological Support to Domestic Heat Meters

Metrological support is considered for domestic heat meters, with the use of test flowmeters and simulation models for the primary flow rate detectors.

Approximating Equations for the Heat Meters of Hot-Water Supply Systems

Direct approximating equations for calculating the specific enthalpy and the density of water, and the inverse equations for platinum resistance heat converters, which are convenient to use for hot-water supply heat meters are recommended.

Metrological Aspects of the Application of GOST R 51649–2000 to Heat Meters for a Water-Based Heat Supply System

The requirements formulated for the metrological characteristics of separate measuring channels of heat meters ensure that the GOST R 51649–2000 requirements concerning errors of thermal energy measurement are satisfied.

The Draft Standard on the State Test Scheme for Means of Measuring Amounts of Heat in Water-Based Heat Supply Systems and Estimating Measurement Errors for Commercial Heat Meters

A description is given of the first draft for a standard: “The State System of Measurements. The state test scheme for means of measuring amount of heat in water-based heat supply systems.” Basic aspects are considered in: “Methods of estimating measurement errors for heat energy and heating medium mass in commercial meters.”