GB/T 40517-2021 English PDF (GB/T40517-2021)

GB/T 40517-2021: Solar thermal storage system for low and medium temperature application
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GB/T 40517-2021
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 27.160
CCS F 12
Solar thermal storage system for low and medium
temperature application
太阳能中低温蓄热装置
ISSUED ON: AUGUST 20, 2021
IMPLEMENTED ON: MARCH 01, 2022
Issued by: State Administration for Market Regulation;
Standardization Administration of PRC.
Table of Contents
Foreword ... 4 
1 Scope ... 5 
2 Normative references ... 5 
3 Terms and definitions... 6 
4 Classification and marking ... 8 
4.1 Classification ... 8 
4.2 Marking ... 9 
5 General ... 10 
5.1 Service life ... 10 
5.2 Structural requirements ... 10 
5.3 Material and medium requirements ... 10 
5.4 Water quality requirements ... 11 
5.5 Electrical safety ... 11 
6 Technical requirements ... 11 
6.1 General provisions ... 11 
6.2 Appearance ... 12 
6.3 Thermal storage performance ... 12 
6.4 Freezing resistance ... 13 
6.5 Vacuum shock resistance ... 13 
6.6 Pulse pressure ... 13 
6.7 Pressure resistance ... 13 
6.8 Safety performances ... 13 
6.9 Pressure loss ... 14 
7 Test methods ... 14 
7.1 General provisions ... 14 
7.2 Appearance ... 15 
7.3 Thermal storage performance ... 15 
7.4 Freezing resistance ... 23 
7.5 Vacuum shock resistance ... 23 
7.6 Pulse pressure ... 23 
7.7 Pressure resistance ... 23 
7.8 Safety devices ... 23 
7.9 Pressure loss ... 23 
8 Inspection rules ... 24 
8.1 Types of inspections ... 24 
8.2 Exit-factory inspection ... 24 
8.3 Type inspection ... 24 
8.4 Judgment rules ... 24 
9 Markings, instructions, product certificates ... 25 
9.1 Markings ... 25 
9.2 Instructions ... 26 
9.3 Product certificate ... 26 
10 Packaging, transport, storage ... 26 
10.1 Packaging ... 26 
10.2 Transport ... 27 
10.3 Storage ... 27 
Solar thermal storage system for low and medium
temperature application
1 Scope
This document specifies the terms and definitions, classification and marking, general
requirements, technical requirements, test methods, inspection rules, signs, instructions
and product qualification certificates, packaging, transportation, storage of solar
thermal storage system for low and medium temperature application.
This document is applicable to thermal storage systems, that are mainly heated by solar
radiation AND whose working temperature is less than or equal to 150 °C.
2 Normative references
The contents of the following documents constitute essential provisions of this
document through normative references in the text. Among them, for dated references,
only the version corresponding to the date applies to this document; for undated
references, the latest version (including all amendments) is applicable to this document.
GB/T 191 Packaging - Pictorial marking for handling of goods
GB/T 1720 Circle-drawing test of coating films
GB/T 1771 Paints and varnishes - Determination of resistance to neutral salt spray
(fog)
GB/T 1865 Paints and varnishes - Artificial weathering and exposure to artificial
radiation - Exposure to filtered xenon-arc radiation
GB 2894 Safety signs and guideline for the use
GB 4706.1 Household and similar electrical appliances - Safety - Part 1: General
requirements
GB 5749 Standards for drinking water quality
GB/T 9969 General principles for preparation of instructions for use of industrial
products
GB/T 13384 General specifications for packing of mechanical and electrical
product
GB/T 18713 Solar water heating systems - Design, installation and engineering
acceptance
GB/T 19141 Specification of domestic solar water heating systems
GB/T 20095 Assessment code for performance of solar water heating systems
GB/T 28745 Test methods for storage tank of domestic solar water heating system
GB/T 28746 Specification of storage tank of domestic solar water heating system
ISO 9488 Solar energy - Vocabulary
3 Terms and definitions
The terms and definitions, which are defined in GB/T 19141, GB/T 28746, ISO 9488,
as well as the following terms and definitions, apply to this document.
3.1
Solar thermal storage system of low and medium temperature application
A thermal storage system, which stores the heat absorbed by the solar collector, in
the form of sensible heat and/or latent heat AND has a working temperature of less
than or equal to 150 °C.
3.2
Thermal storage medium
A medium, that stores heat in the form of sensible and/or latent heat, by utilizing the
thermal storage properties of matter.
3.3
State at completion of thermal storage
The state of the thermal storage system -- when the circulating working medium on
the thermal storage side of the thermal storage system is at the rated flow rate; the
inlet temperature reaches the nominal maximum thermal storage temperature of the
product; the difference between the inlet temperature and the outlet temperature does
not exceed 2 °C.
3.4
State at completion of heat supply
The state of the thermal storage system -- when the circulating working medium on
include thermal storage tanks and soil-buried-pipe thermal storage systems. It shall
provide the thermal storage capacity, heat supply capacity, thermal storage efficiency,
average heat supply power of the custom installed thermal storage systems, during the
test period. It shall also provide the annual heat loss rate, for the thermal storage tank.
6.2 Appearance
6.2.1 The surface of the shell of the thermal storage system shall be flat, without cracks
or obvious scratches.
6.2.2 The inlet and outlet of the thermal storage system shall have clear signs, which
indicate the interface function and flow direction.
6.2.3 After 72 h of the salt spray resistance test, the shell coating of the thermal storage
system shall be complete without cracks, falling skin, peeling off, rust. After the coating
adhesion test, the shell coating shall not peel off AND reach the grade 1 specified in
GB/T 1720; the specular reflectance of visible light on the surface of the shell material
shall not be greater than 0.10. After the aging test, the shell material shall be free of
fading or discoloration.
6.3 Thermal storage performance
6.3.1 Effective thermal storage capacity
The measured value of the effective thermal storage capacity shall not be lower than
95% of the nominal value.
6.3.2 Thermal storage efficiency
The measured value of thermal storage efficiency shall not be lower than 90% of the
nominal value.
6.3.3 Average heat supply power
The measured value of the average heat supply power shall not be lower than 95% of
the nominal value.
6.3.4 Stationary heat loss rate
The stationary heat loss rate shall not be greater than 6%.
6.3.5 Effective thermal storage capacity per unit mass
The measured value of the effective thermal storage capacity per unit mass of the phase
change thermal storage system shall not be lower than 95% of the nominal value.
6.3.6 Decay rate of phase change thermal storage system
After the phase change thermal storage system has undergone continuous and repeated
thermal storage-heat supply tests, AND after reaching the indicated number of tests, the
decay rate of the phase change thermal storage system is calculated, according to the
last measured value of heat supply capacity and the effective heat supply capacity.
6.3.7 Annual heat loss rate of thermal storage tank
It shall give the annual heat loss rate of the thermal storage tank.
6.4 Freezing resistance
After the freezing resistance test is carried out, under the conditions of -20 °C ± 2 °C,
the closed thermal storage system shall be free from leakage, breakage, deformation,
destruction; the safety pressure relief device shall not freeze.
6.5 Vacuum shock resistance
Under the absolute vacuum pressure of 33 kPa, the closed thermal storage system shall
not have any deformation, that affects the safety.
6.6 Pulse pressure
After the closed thermal storage system has undergone 80000 pulse pressure tests, the
welds shall be free of leakage, obvious deformation, cracking.
6.7 Pressure resistance
The thermal storage system, heat exchanger, connecting pipeline shall meet the
requirements for rated working pressure; there shall be no penetration, deformation or
crack phenomenon, under the test pressure. If there is no express description, the closed
working pressure shall not be less than 0.6 MPa, the test pressure shall be 1.5 times the
rated working pressure; the open test pressure shall be 0.065 MPa.
6.8 Safety performances
6.8.1 The closed thermal storage system, heat exchanger, connecting pipeline shall be
equipped with safety pressure relief protection device.
6.8.2 The leakage current, electric strength, grounding resistance of the thermal storage
system of the live part, at the working temperature, shall meet the requirements of GB/T
Description of index number:
1 - Solar thermal storage system of low and medium temperature application; 2 - Cooling
equipment; 3 - Expansion tank; 4 - Filter; 5 - Circulating pump; 6 - Heating equipment; 7 -
Flow control valve; 8 - The outlet pressure sensor of circulating working medium; 9 - The inlet
pressure sensor of circulating working medium; 10 - The outlet temperature sensor of
circulating working medium; 11 - The inlet temperature sensor of circulating working medium;
12 - Circulating medium flow sensor; 13 - Circulating medium outlet valve; 14 - Circulating
medium inlet valve; 15 - Front valve of cooling equipment; 16 - Bypass valve of cooling
equipment; 17 - Front valve of heating equipment; 18 - Bypass valve of heating equipment.
Figure 1 -- Schematic diagram of the test system for thermal storage
performance
7.3.2 Test conditions
7.3.2.1 Fill enough thermal storage medium and circulating working medium, to the
rated working pressure.
7.3.2.2 The temperature of the test environment shall be 20 °C ± 5 °C; the relative
humidity shall not be higher than 75%. The ambient temperature sensor shall be placed
in the louver box; the installation position shall not be 1 m farther than the device under
test; the height shall be 1/2 of the height of the device under test.
7.3.2.3 Set the control system of the thermal storage system, according to the
parameters recommended by the manufacturer.
7.3.3 Test method
7.3.3.1 Pre-operation test
Before the thermal storage-heat supply test, a pre-operation test shall be carried out,
according to the following method.
a) Connect the test system to the inlet and outlet of the thermal storage side of the
thermal storage system. Open the valve of the thermal storage pipeline. Close the
valve of the heat supply pipeline.
b) Start the circulating water pump. Adjust the flow rate of the circulating working
medium, on the thermal storage side, to the rated working condition. Control the
inlet temperature to increase, from the nominal minimum temperature. After
every increase of 10 °C, keep the temperature difference between the inlet and
outlet stable and not greater than 2 °C, for at least 5 minutes. Continue to heat up,
until the inlet temperature reaches the nominal maximum temperature. The
control accuracy of the inlet temperature shall be ±0.2 °C; the thermal storage
system stores heat in steps.
c) When the inlet temperature of the circulating working medium, on the thermal
storage side, reaches the maximum temperature AND the thermal storage system
reaches the state of completion of thermal storage, close the valve of the
circulating pipeline on the thermal storage side; stabilize the thermal storage
system for at least 20 minutes.
d) Connect the test system to the inlet and outlet of the heat supply side of the thermal
storage system. Open the valve of the heat supply pipeline. Close the valve of the
thermal storage pipeline.
e) Start the circulating water pump. Adjust the heating flow to reach the rated
working condition. Control the inlet temperature to the nominal minimum
temperature. Where there is no nominal minimum temperature, control the inlet
temperature to 30 °C; the control accuracy of the inlet temperature shall meet
±0.2 °C. Make the thermal storage system continuously supply heat to the outside.
f) When the inlet temperature of the circulating working medium, on the heating side,
is kept at the minimum temperature AND the thermal storage system reaches the
state of completion of heat supply, close the valve on the heating side; stabilize
the thermal storage system for at least 20 minutes.
g) Perform the process of a) ~ f) again; at least 2 pre-operation tests shall be
completed.
7.3.3.2 Thermal storage test
After the completion of the pre-operation test, the thermal storage test shall be carried
out, according to the thermal storage process, which is described in 7.3.3.1. During the
test, the circulating working medium flow on the thermal storage side, the inlet and
outlet temperatures, the collection and recording time interval, the thermal storage time
shall be recorded. Use the formula (1), to calculate the single thermal storage capacity
Qs:
Where:
Qs - The single thermal storage, in kilowatt-hour (kWh);
ρs - The density of the circulating working medium, on the thermal storage side, in
kilograms per cubic meter (kg/m3);
cs - The specific heat capacity of the circulating working medium, on the thermal
storage side, in kilojoules per kilogram Celsius [kJ/(kg • °C)];
Vs - The volume flow of circulating working medium, on the thermal storage side,
test, in seconds (s);
i - the ith record of the heating test;
Ta - The total recording number of heating test.
7.3.3.4 Stationary heat loss rate test
After completing at least 2 consecutive thermal storage-heat supply tests, according to
the methods of 7.3.3.2 and 7.3.3.3, conduct a thermal storage test, according to the
method of 7.3.3.2. Then let the thermal storage system stand for 8 hours, according to
the method of 7.3.3.3. Carry out a heating test again. In this time, the measured value
of single heat supply is recorded as Qa,...