Wireless Sensor Network, 2010, 2, 250-253
doi:10.4236/wsn.2010.23034 Published Online March 2010 (http://www.scirp.org/journal/wsn)
Copyright © 2010 SciRes. WSN
Study on the Wireless Heat Meters
Rujian Ma, Xueyan Yang, Xiao Wang, Enping Zhang
School of Control Science and Engineering, University of Jinan, Jinan, China
E-mail: rjma@ujn.edu.cn
Received August 16, 2009; revised September 21, 2009; accepted October 19, 2009
The design of a new type heat meters based on RFID technology are presented in this paper. By use of RFID
technology in heat meters, the data can be exchanged between heat meters and heat supplying department by
RF cards. The information can be transmitted in a non-contact way. In this way, the purpose of automatic
identification can be achieved. The experimental study of the heat meters is also performed in the paper. The
results show that the new type of heat meters can meet the demands of users. Compared with the ordinary
heat meters, the new type of heat meters have the advantages of small in meter volume, high accuracy, no
impact of water quality and good reliability.
Keywords: Heat Meters, Design, Experimental Study, RFID
1. Introduction
Radio frequency identification (RFID) technology is a
non-contact automatic identification technology [1].
Based on the wireless data communication technology,
the RFID technology has been widely used for wireless
remote meter-reading technology and provides a suffi-
cient technology foundation. At the present, the central
heating supply in the urban area of China, waste of en-
ergy and unreasonable charges by the heating area, these
problems have restricted the further development of cen-
tral heating. In the implementation of structural reform in
the urban heating, heat meters are the key equipment in
heating metering and charging control system, which can
achieve the metering of urban central heating household
and energy charges in accordance with the implementa-
tion of heat, and this has gradually become a new hot
industry. To make the study of intelligent heat meters
based on RFID technology, we consulted the Interna-
tional Organization of Legal Metrology OIML-R75 rules
and the European standards EN1434 heat meters which
are most advanced in the world, also we draw lessons
from European advanced technology and experience of
similar products, these heat meters can realize not only
for the centralized hot household heat metering, but also
the non-contact measurement of data transmission and
the control of clearing transactions. As a result, the heat
meters provide the possibility of intelligent management
in cities and a firm material foundation for the digital
communities and cities, which can bring high social and
economic benefits.
Heat meters are the terminal equipments of the heat
metering management system, as shown in Figure 1.
They exchange data with the department of heat meter-
ing by radio frequency (RF) cards. As an important as-
pect of RFID technology, the RF cards achieve non-
contact transmission of information by using radio fre-
quency signals through space coupling. Furthermore,
they can achieve the purpose of automatic identification
through the transmission of information.
In heat metering management system, each user gets a
new RF card when installed new equipment. Before us-
ing heat meters, users must open accounts in the depart-
ment and the management system establishes detailed
information for each user. After opening accounts, users
buy heat according to their actual needs of the heat re-
quired and bring about closer ties between RF card and
their own heat meters. From the information security
point of view, in the card all user information, heat data
calorie and other management information is transmitted
Figure 1. Diagram of the heat supplying management system.
R. J. Ma ET AL.251
in the form of encryption, heat meters do the corre-
sponding decryption work when they accept. At the same
time, heat meters transmit the user's use of heat, the re-
maining heat value, the corresponding record in history
and heat meters state information to heat supplying de-
partment by RF card. Heat supplying department analy-
ses and compares the historical data they collected, and
obtains a large number of heating data, these data pro-
vide strong data support for the department to make de-
2. Design of Heat Meters
Heat meters consist of two major parts, the RF card and
smart heat metes.
The Mifare One of Philips chips (referred to M1 card)
is a kind of commonly used RF card. The parameters of
the card are: 8K in storage capacity, 10 years of data
retention, 100,000 cycles for rewriting, unlimited time
for reading, and no battery needed. The card has its own
antenna, encryption control logic circuit and communi-
cation logic circuit, inter-national common DES and
cross-RES secrecy algorithm is adopted in the commu-
nication between the card and reader, its confidentiality
performance is very high, with characteristics of fast
anti-collision, high reliability in data communication,
anti-strong electrical interference, moisture-proof, wa-
terproof, convenience, fast and so on [2].
The smart heat metes contains a microprocessor, a
mechanical rotor-type non-magnetic flow sensor, a pair
of temperature sensor, a voltage monitor and radio fre-
quency modules, and so on. The overall structure of the
heat meters is shown in Figure 2.
The microprocessor uses singlechip of MSP430FW425
type for the wireless long-distance transmission calo-
rimeter. Its internal composite signal processor is key
microprocessor of integrating monitor, superior per-
formance, reliable and cost-effective [3]. The current
sensor is mechanical rotor type multi-striation flowmeter
which is improved to comply with the request of
non-magnetic current signal acquisition calibration mod-
ule and measurement characteristic. It is characterized by
a small wheel rotor installed. Signal damping board is
light in weight, wide flow measurement, and high accu-
racy of flow measurement and applicable to poor quality
Figure 2. Overall structure diagram of heat meters.
water etc. [4]. A pair of temperature sensors are used for
measuring temperature and signal of difference in tem-
perature about heat exchanger inlet and outlet, the preci-
sion of the sensors less than 0.1 [5]. Integrating moni-
tor is hardcore. On one hand, it collects and calibrates the
flow rate signal, temperature and signal of difference in
temperature integration demonstration quantity of heat of
non-magnetic flowmeter. On the other hand, it uses RF
transport module to transports data.
Control software of heat meters are designed based on
the modularizaion method, including radio frequency
read-write module, non-magnetic flowmeter scan module,
flow rate module and so on. Each part functionally inde-
pendent designed, effectively to guarantee the reliability
of the scale of intelligent hot work. The table with appli-
cability and flexibility and humanized design concept are
full considered in the design, heat meters based on RFID
technology has superior intelligence and fully meets the
market demand. Flow chart of the main program and the
card interrupt program are shown in Figures 3 and 4.
3. Experimental Study
Three heat meters of DN20 type are used for the proto-
type test. The test includes accelerated wear test, metro-
logical characteristic test and data communication test.
The accelerated wear test requires that the meter is
continuously running 300 hours under the maximum
flow rates. The maximum flow rate of this meter is 5000
kg/h. All the three meters are in good working situation
after the test.
Figure 3. Flow chart of the software program.
Copyright © 2010 SciRes. WSN
R. J. Ma ET AL.
Figure 4. Flow chart of the card interrupt program.
Metrological characteristic test includes temperature
test and flow rate test. The measuring points for the tem-
perature test are 10, 50 and 90 degrees Centigrade, repre-
senting the low, medium and high temperatures respec-
tively. The measurement results of temperatures are listed
in Table 1. It can be seen from the table that all the data
is less than the permit error of level 2 meters (3.5%). The
measurement of flow rates is performed in three tem-
perature points representing the low, medium and high
temperatures. The results are shown in Figures 5, 6 and 7.
It can be seen from the figures that all the data is less than
the permit error of level 2 meters.
The test items of data communication test include Dis-
tance of data reading & writing, resetting data, data sum-
mation, data transfer and replacement of cards and meters.
The measurement results of the data communication
01000 20003000 40005000
flow rate, kg/h
Relative error (%)
Prototype APrototype B
Prototype CPermit error
flow rate (kg/h)
Figure 5. Measurement errors of flow rates at 10 degree
01000 2000 3000 4000 5000
flow rate, k
Relative error (%)
Prototype APrototype B
Prototype CPermit error
flow rate (kg/h)
Figure 6. Measurement errors of flow rates at 50 degree
flow rate
0 1000200030004000500
flow rate, kg/h
Relative error (%)
Prototype APrototype B
Prototype CPermit error
flow rate (kg/h)
Figure 7. Measurement errors of flow rates at 90 degree
test are listed in Table 2. Compared with the perform-
ance required of the meters (also listed in the table) indi-
cates that all the performance indexes are satisfied with
the requirement of the meters.
Table 1. Measurement results of temperatures.
Maximum errors (%)
Test points ()Prototype A Prototype B Prototype C
10, 50 and 90 1.17 1.92 0.79
Table 2. Results of data communication tests.
Prototype numbers
Test items Performance
required No. A No. B No. C
Distance of
data reading
& writing
2.0 cm2.2 cm2.4 cm2.3 cm
The valve is
closed after data
Normal Normal Normal
The valve will
be open after
data summation
Normal Normal Normal
Will be work
normally after
the data transfer
Normal Normal Normal
of cards and
Will be work
normally after
the replacement
Normal Normal Normal
Copyright © 2010 SciRes. WSN
R. J. Ma ET AL.
Copyright © 2010 SciRes. WSN
4. Conclusions
A new type of heat meter is designed based on RFID
technology in this paper. This type of heat meters can
provide centralized heat metering, residence intelligence,
management digitization and information system man-
agement with new plan. The experimental study is also
presented in the paper. The results indicate that the heat
meters have high accuracy in measurement, no impact of
water quality, good reliability and low power consumption.
5. Acknowledgements
This project is supported by Research Foundation of
University of Jinan (XKY0806) and Key Subject Re-
search Foundation of Shandong Province.
. References
[1] Y. Shen, “Application of RFID technology in mana-
gement of college teaching,” Instrumentation Analysis
Monitoring, No. 1, 2008.
[2] X. Yi, “Application of Mifare one RF card in prepayment
electric meter,” Process Automation Instrumentation, Vol.
28, No. 8, 2007.
[3] S. Guo, “Design of RFID reader based on MCUMSP430,”
Journal of Jilin University, Vol. 28, No. 2, 2007.
[4] X. Yang, “Design of digital water meter based on
MSP430FW425 MCU scan IF module,” Computer
Engineering and Applications, Vol. 42, No. 18,42, 2006.
[5] X. Wei, “MSP430 singlechip interface technology and
system design examples,” Beijing University of Aeronau-
tics & Astronautics Press, 2002.