PUBLIC REVIEW DRAFT, SEPTEMBER 2008KENYA STANDARD  KS 1852-2:2008  
ICS 27.160 
  
 
 
  
 
  
 
  
 
Thermal solar systems and components — 
Factory made systems — Part 2: Test methods 
 
 
 
 
 
 
  
 
  
 
Public Review Draft, September 2008  
 
 
 
 
  
 
  
 
  
 
© KEBS 2008 Edition 1.0 
 PUBLIC REVIEW DRAFT, SEPTEMBER 2008KS 1852-2:2008 
ii © KEBS 2008 — All rights reserved  
TECHNICAL COMMITTEE REPRESENTATION 
 
The following organizations were represented on the Technical Committee 
 
Kenital Solar (K) Ltd  
ASP Solar (Kenya) Ltd  
Sollatek Ltd  
Department of Electrical & Electronic Engineering, JKUAT  
Renewable Energy Department, Ministry of Energy  
Chloride Exide Kenya Limited  
Energy Alternatives Africa Ltd  
Solarnet  
Automotive and Industrial Battery Manufacturers (AIBM) (K) Ltd 
RENCON Associates  
Telesales Solar Ltd 
Kenya Industrial Research and Development Institute, KIRDI 
Kenya Bureau of Standards — Secretariat 
 
 
 
 
  
 
 
 
 
  
REVISION OF KENYA STANDARDS 
 
In order to keep abreast of progress in industry, Kenya standards shall be regularly reviewed. Suggestions for 
improvement to published standards, addressed to the Managing Director, Kenya Bureau of Standards, are 
welcome. 
 
© Kenya Bureau of Standards, 2008 
 
Copyright. Users are reminded that by virtue of Section 25 of th e Copyright Act, Cap. 12 of 2001  of the Laws of Kenya, copyrig ht 
subsists in all Kenya Standards and except as provided under Section 26 of this Act, no Kenya Standard produced by Kenya Bureau  of 
Standards may be reproduced, stored in a retrieval system in any form or transmitted by any means without prior permission in w riting 
from the Managing Director. 
 
 
 
 
 
 
   
 
 
 
 
 PUBLIC REVIEW DRAFT, SEPTEMBER 2008KS 1852-2:2008 
ICS 27.160 
© KEBS 2008 — All rights reserved iii  
 
 
 
 
 
 
 
 
  
 
 
Thermal solar systems and components — 
Factory made systems — Part 2: Test methods 
 
 
  
 
 
 
 
  
 
 
 
KENYA BUREAU OF ST ANDARDS (KEBS) 
 
Head  Office:  P.O. Box 54974, Nairobi-00200, Tel.: (+254  020) 605490, 602350, Fax: (+254 020)  604031 
E-Mail: info@kebs.org,  Web:http://www.kebs.org   
 
KEBS Coast Region 
P.O. Box 99376, Mombasa 80100 
Tel: (+254 041) 229563, 230939/40 
Fax: (+254 041) 229448 
E-mail: kebs-msa@swiftmombasa.com  KEBS Lake Region 
P.O. Box 2949, Kisumu 40100 
Tel: (+254 057) 23549,22396 
Fax: (+254 057) 21814 
E-mail: kebs-ksm@swiftkisumu.com  KEBS North Rift Region 
P.O. Box 2138, Nakuru 20100 
Tel: (+254 051) 210553, 210555
 PUBLIC REVIEW DRAFT, SEPTEMBER 2008KS 1852-2:2008 
iv © KEBS 2008 — All rights reserved  
Foreword 
 
This Kenya standard was developed by the Renewable Energy Resources Technical Committee under the supervision of the Electrical Industry Standards Committee and is in accordance with the procedures of the 
Bureau. 
 
Drinking water quality 
 
In respect of potential adverse effects on the quality of water intended for human consumption, caused by the 
product covered by this standard: 
 a) This standard provides no information as to whether the product may be used without restriction; 
 
b) It should be noted that, while awaiting the adoption of verifiable Kenya criteria, existing national regulations concerning the use and/or the characteristics of this product remain in force. 
 Factory Made and Custom Built solar heating systems  
The standards KS 1852-1 as well as KS 1852-2 and the standards KS 1855-1 to KS 1855-3 distinguish two 
categories of solar heating systems: Factory Made  solar heating systems and Custom Built  solar heating 
systems. The classification of a system as Factory Made or Custom Built is a choice of the final supplier, in 
accordance with the following definitions. 
 
Factory Made solar heating systems  are batch products with one trade name, sold as complete and ready 
to install kits, with fixed configurations. Systems of this category are considered as a single product and 
assessed as a whole. If a Factory Made Solar Heating System is modified by changing its configuration or by changing one or more of its components, the modified system is considered as a new system for which a new 
test report is necessary. Requirements and test methods for Factory Made solar heating systems are given in 
KS 1852-1 and KS 1852-2. 
 
Custom Built solar heating systems  are either uniquely built, or assembled by choosing from an 
assortment of components. Systems of this category are regarded as a set of components. The components 
are separately tested and test results are integrated to an assessment of the whole system. Requirements for 
Custom Built solar heating systems are given in KS 1855-1; test methods are specified in KS 1855-2 and KS 
1855-3. Custom Built solar heating systems are subdivided into two categories:  
⎯ Large Custom Built systems  are uniquely designed for a specific situation. In general HVAC 
engineers, manufacturers or other experts design them. 
 
⎯ Small Custom Built systems  offered by a company are described in a so-called assortment file, in 
which all components and possible system configurations, marketed by the company, are specified. 
Each possible combination of a system configuration with components from the assortment is considered 
as one Custom Built system. 
 
Table 1 shows the division for different system types: 
  PUBLIC REVIEW DRAFT, SEPTEMBER 2008KS 1852-2:2008  
© KEBS 2007 — All rights reserved v Table 1 ⎯ Division for factory made and custom built solar heating systems 
 
Factory Made Solar Heating 
Systems (KS 1852-1, -2) 
 Custom Built Solar Heating Systems (KS 1855-1, -
2, -3) 
 
Integral collector-storage 
systems for domestic hot water 
preparation 
 Forced-circulation systems for hot water preparation 
and/or space heating, assembled using components 
and configurations described in a documentation file 
(mostly small systems) 
 
Thermosiphon systems for 
domestic hot water preparation 
  
 
Forced-circulation systems as batch product with fixed configuration for domestic hot 
water preparation 
 Uniquely designed and assembled systems for hot 
water preparation and/or space heating (mostly large systems) 
 
 
NOTE 1 Forced circulation systems can be classified either as Factory Made or as Custom Built, depending on the market 
approach chosen by the final supplier. 
 
NOTE 2 Both Factory Made and Custom Built systems are performance tested under the same set of reference conditions as 
specified in Annex B of KS 1852-2 and Annex A of KS 1855-2. In practice, the installation conditions may differ from these 
reference conditions. 
 
NOTE 3 A Factory Made system for domestic hot water preparation may have an option for space heating, however this 
option should not be used or considered during testing as a Factory Made system. 
 
 PUBLIC REVIEW DRAFT, SEPTEMBER 2008KS 1852-2:2008 
vi © KEBS 2008 — All rights reserved  
Contents 
 
1 Scope ......................................................................................................................... ................................ 1  
2 Normative references .......................................................................................................... ....................... 1  
3 Terms and definitions ......................................................................................................... ........................ 1  
4 Symbols and abbreviations ..................................................................................................... ................... 1  
5 Testing ....................................................................................................................... ................................. 2  
Annex A (normative)  Thermal performance presentation sheet ......................... ........................................................ 15  
Annex B (normative)  Reference conditions for performance prediction .......... ........................................................ 17  
Annex C (informative)  Extreme climate test procedure for the assessment of the frost resistance of solar DHW 
systems with outdoor tank...................................................................................................... ........................... 21  
Annex D (informative)  Ageing test for thermostatic valves.................................................................................. 36  
Annex E (informative)  Lightning protection test for solar heating systems ........................................................... 38  
Annex F (informative)  Lightning Protection testing sheet ......................................................................................... 41  
Bibliography .................................................................................................................. .................................... 45  
 
 
   PUBLIC REVIEW DRAFT, SEPTEMBER 2008KENYA STANDARD KS 1852-2:2008  
© KEBS 2008 — All rights reserved 1  
 
Thermal solar systems and components — Factory made systems — 
Part 2: Test methods 
 
 1 Scope 
 
This Kenya Standard specifies test methods for validating the requirements for Factory Made Thermal Solar 
Heating Systems as specified in KS 1852-1. The standard also includes two test methods for thermal 
performance characterization by means of whole system testing. 
 
2 Normative references 
 
The following referenced documents are indispensable for the application of this Kenya Standard. For dated references, only the edition cited applies. For undate d references, the latest edition of the referenced 
document (including any amendments) applies. 
 
KS 1851-2, Thermal solar systems and components 
⎯ Factory made systems ⎯ Part 2: Test methods  
 
KS 1852-1, Thermal solar systems and components ⎯ Factory made systems ⎯ Part 1: General 
requirements  
 
KS 1855-2, Thermal solar systems and components — Custom built systems — Part 2: Test methods  
 
IEC 60335-1, Household and similar electrical appliances ⎯ Safety ⎯ Part 1: General requirements  
 
IEC 60335-2-21, Household and similar electrical appliances ⎯ Safety ⎯ Part 2-21: Particular requirements 
for storage water heaters  
 
ISO 9488, Solar energy ⎯ Vocabulary  
 
ISO 9459-1, Solar heating ⎯ Domestic water heating systems ⎯ Part 1: Performance rating procedure using 
indoor test methods  
 
ISO 9459-2, Solar heating ⎯ Domestic water heating systems ⎯ Part 2: Outdoor test methods for system 
performance characterization and yearly performance prediction of solar-only systems  
 
ISO 9459-5, Solar heating ⎯ Domestic water heating systems ⎯ Part 5: System performance 
characterization by means of whole-system tests and computer simulation  
 
3 Terms and definitions 
 
For the purposes of this Kenya Standard, the terms and definitions given in ISO 9488 and KS 1852-1 apply.  
4 Symbols and abbreviations 
 
Qaux, net  net auxiliary energy demand of a solar heating sy stem delivered by the auxiliary heater to the store 
or directly to the distribution system (see 5.8.3.2) 
 
Qd heat demand 
 
QL energy delivered at the outlet of the solar heating system 
 PUBLIC REVIEW DRAFT, SEPTEMBER 2008KS 1852-2:2008 
2 © KEBS 2008 — All rights reserved Qpar parasitic energy (electricity) for the collector loop pump(s) and control unit 
 
Hc hemispherical solar irradiation in the collector plane 
 
Ql store heat loss 
 Q
ohp heat diverted from the store as active overheating protection, if any 
 Q
sol heat delivered by the collector loop to the store 
 
5 Testing 
 
5.1 Freeze resistance 
 
5.1.1 General 
 
The following checks are given to ensure that the protective antifreezing provisions are operating properly. There are many possible forms of protective provisions, and the testing authority shall first identify which 
method has been employed. 
 
The provision shall then be checked in accordance with the appropriate section of the following list (see 5.1.2 
to 5.1.6) in accordance with the manufacturer's recommendations.  5.1.2 Systems using antifreeze fluid 
 
The system components which are exposed to low ambient temperature are filled with an antifreeze fluid, 
usually a glycol/water mixture, having a low enough freezing point.  
For these systems, no freezing test is performed. However, if no sufficient data is available on the freezing point of the antifreeze fluid, the freezing point shall be measured and checked against the minimum system 
temperature as given by the manufacturer. 
 
NOTE In general, the minimum allowed temperature of the system is equal to the freezing point of the antifreeze fluid. If the 
concentration of some antifreeze fluids ⎯ like glycol's ⎯ exceeds a certain limit, they can freeze without damaging the system. In this 
case the minimum allowed temperature can be lower than the freezing point of the antifreeze fluid. 
 
Check the freezing point by measuring the glycol concentration (e.g. using a portable refractometer). The 
freezing point should be as recommended by the manufacturer in agreement with the local climate (minimum 
expected air temperature, radiative cooling of the collectors). 
 
The composition of the fluid shall be checked to see whether it is in accordance with the manufacturer's 
specifications. 
 5.1.3 Drain-back systems 
 
The fluid in the system components, which are exposed to low ambient temperature, is drained into a storage 
vessel for subsequent reuse when freezing danger occurs. 
 The collector loop piping should be in accordance with the manufacturer's recommendations in the installer 
manual and if there is no instruction, according to reference conditions given in Annex B.  
Filling may be observed from the pressure gauge or from water level indicator. Switch the pump on, and 
observe the pressure gauge or water level indicator. If the system does not include a pressure gauge or level 
indicator, other means for checking filling provided by th e manufacturer shall be used in accordance with the 
instruction manual. 
 
Drain-back may be observed from the decreasing reading of the pressure gauge or water level indicator. 
Switch the pump OFF, and observe the pressure gauge or water level indicator. If the system does not PUBLIC REVIEW DRAFT, SEPTEMBER 2008KS 1852-2:2008 
© KEBS 2008 — All rights reserved 3 include a pressure gauge or level indicator, other means for checking drain-back provided by the 
manufacturer shall be used in accordance with the instruction manual. It might be necessary to repeat the 
check at high storage temperature (90 °C) in order to insure drain-back in all situations (see 5.2). 
 
5.1.4 Drain-down systems 
 The fluid in the system components, which are exposed to low ambient temperature, is drained and run to 
waste when freezing danger occurs. 
 Check the proper opening and closing of the vacuum relief valve. 
 
If there is a solenoid drain valve independent of the control unit, simulate the opening temperature.  
If there is a non-electrically operated freeze-protection valve, a check can be made using a freezing spray. 
The temperature-sensing element shall be sprayed. The measured temperature of the valve opening is to be compared with the nominal value given by the manufacturer. It is important that the sensing part of the freeze-
protection valve be properly placed. 
 
The collector loop piping should be in accordance with the manufacturer's recommendations in the installer 
manual and if there is no instruction, according to reference conditions given in Annex B.  
Open drain-down valve manually and measure the drain rate with a vessel and a stop-watch.  
If the system uses an electrically operated freeze-protection valve, drain down shall be checked while 
interrupting the power.  
5.1.5 Freeze protection and control functions combined  
For systems where the freeze-protection and control functions are combined, the control unit shall be checked 
as follows:  Set the simulated temperature of the freeze-protection sensor to a value deactivating the freeze protection. 
Decrease the simulated temperature slowly. Measure the temperature T
FP (freeze-pratection)  of the related actuator. 
Compare it with the nominal value given by the manufacturer. 
 
5.1.6 Other systems 
 
For all other systems, the pump control system, drain-down valve or any other freeze protection device or system shall be checked to the manufacturer's specification and the minimum allowed temperature specified 
by the manufacturer. For ICS systems, or other SDHW systems with the tank placed outside, special frost 
resistance tests should be carried out, as described in C.1.  
5.2 Over temperature protection 
 
5.2.1 Purpose 
 
The purpose of this test is to determine whether the solar water heating system is protected against damage 
and the user is protected from scalding hot water delivery after a period of no hot water draw and failure of electrical power. 
 
5.2.2 Apparatus 
 
The following apparatus is required: 
 
a) A pyranometer having the minimum characteristics specified in KS 1851-2, to measure the hemispherical 
solar irradiance, or the short wave irradiance from a solar simulator lamp if the test is to be conducted 
inside a solar simulator chamber. PUBLIC REVIEW DRAFT, SEPTEMBER 2008KS 1852-2:2008 
4 © KEBS 2008 — All rights reserved  
b) Equipment to measure the temperature, flow rate and volume of hot water drawn from the system. 
 
c) An outdoor or an indoor test stand for installing the solar hot water system with the collector array at the 
manufacturer's specified angle of inclination. 
 
d) A temperature and pressure controlled water supply within the range of 5 °C to 25 °C and 200 kPa to 600 
kPa or the manufacturer's maximum working pressure whichever is less. 
 This test may be conducted using a solar simulator or outdoors. 
 5.2.3 Procedure 
 
The system, both as described in the installation manual and as installed on the test facility, shall be first 
checked on overheating safety, e.g. if safety valves and other overheating protection devices are present and 
installed at the right place, if there are no valves between components and relief valves etc. For systems 
containing antifreeze fluids, it shall be checked whether sufficient precautions have been taken to prevent the 
antifreeze fluid from deterioration as a result of high temperature conditions (See also 5.6). 
 
Furthermore, if non-metallic materials are used in any circuit, the highest temperature in the circuit shall be measured during the over temperature protection test, for use in the pressure resistance test. 
 The procedure of testing shall be as follows: 
 
a) Assemble the solar water heating system according to the installation instructions  with the collector array 
oriented towards solar noon for the outdoor test, or the simulator lamp may be adjusted to normal 
incidence for the indoor test. 
 
b) Charge the system from the water supply and, for pressurized storage tanks, maintain the water supply 
pressure. 
 
c) Energize the system as per installation instructions. 
 d) (i) For the outdoor test, operate the system for a minimum of 4 consecutive days without any hot water 
withdrawal and until the collector array has been subjected to 2 consecutive days in which the solar, irradiation on the plane of the collector array has exceeded 20 MJ/m
2 per day and the ambient 
temperature has exceeded 20 °C during solar noon. 
 
(ii) For the indoor test, operate the system without an y hot water withdrawal at an ambient temperature 
of (25 ± 2) °C and a minimum solar lamp irradiance of 1000 W/m2 at the plane of the collector array, 
measured and with a uniformity as specified in ISO 9459-1, 6.3.1.2 for a 5 h period or until the 
collector array drains. 
 
e) (i) For the outdoor test, disconnect all electrical power to the system and continue to operate the system 
until the solar irradiation on the plane of the collector array has exceeded 20 MJ/m2 per day or until the 
collector array drains. 
 
(ii) For the indoor test, disconnect all electrical power  to the system and subject the system to a solar 
lamp irradiance of 1000 W/m2 at the plane of the collector array for an additional 4 h or until the 
collector array drains. 
 
f) Immediately begin to withdraw a volume of water greater than the total volume of water in the system at a 
rate of 2 × 10-4 ± 3 × 10-5 m3/s (10 ± 1 L/min.) 
 
5.2.4 Reporting requirements 
 
The following results shall be reported: PUBLIC REVIEW DRAFT, SEPTEMBER 2008KS 1852-2:2008 
© KEBS 2008 — All rights reserved 5  
a) The make and model identification of the system including ancillary scald and over temperature protection 
devices fitted. 
 
b) The inclination of the collector array. 
 
c) A record of temperature of the hot water withdrawn from the system versus time and the total volume of 
water withdrawn. Note the presence of steam if observed. 
 d) Details of the condition of the system and individual components following the test or any failure modes 
during the test with particular regard to any defects which may affect the serviceability of the system such as the swelling of pipes and components or fluid leakages. 
 
5.3 
Pressure resistance  
 
5.3.1 Purpose 
 The purpose of this test is to evaluate hydraulic pressure rating of all components and interconnections of a solar water heating system when installed according to the manufacturer's instructions. 
 
5.3.2 Apparatus 
 
The apparatus shall consist of the following: 
 
a) suitable platform and support structure for installation of the system 
 b) pressure regulated hydraulic pressure source 
 
c) pressure gauge suitable to determine the test pressure to within 5 %  
d) bleed valve  
e) isolation valve 
 
5.3.3 Safety precaution 
 
An explosion safe enclosure is recommended when testing systems that have an integral expansion space or 
tank that contains entrapped air. 
 
5.3.4 Procedure 
 The system, both as described in the installation manual and as  installed on the test facility, shall be first 
checked on pressure safety, e.g. if safety valves and other overheating protection devices are present and 
installed at the right place, if there are no valves between components and relief valves etc. 
 The duration of the test is 15 min for metallic material. If a non-metallic material is used in any circuit, this 
circuit shall be pressure tested for 1 h at the highest temperature measured during the over temperature 
protection test +10 °C. 
 
a) Install the solar water heating system on the test platform in accordance with the manufacturer's 
instructions. 
 b) Disable the pressure relief valves, if applic able, to prevent their opening during testing. 
 c) Connect the pressure gauge and bleed valve at the hot water outlet of the system.  PUBLIC REVIEW DRAFT, SEPTEMBER 2008KS 1852-2:2008 
6 © KEBS 2008 — All rights reserved d) Connect the isolation valve and hydraulic pressure source, using water as the test fluid, to the cold water 
inlet of the system. 
 
e) Fill the potable water side of the system using the hydraulic pressure source and bleed all air, as 
possible, out of the system through the bleed valve at the hot water outlet of the system. 
 
f) Apply a hydraulic pressure equal to 1.5 times the manufacturer's stated maximum working pressure. 
 
g) Isolate the pressure source by closing the isolation valve and record the readings of the pressure gauge 
at the beginning and end of the next 15 min interval. 
 h Release the system pressure through the bleed valve and record any visible permanent deformation and 
water leakage from system components and inter connections. 
 i) Disconnect the bleed valve, pressure gauge, isolation valve and hydraulic pressure source from the 
system. 
 For those systems not constructed with a heat exchanger and a separate pressurized heat transfer loop, the 
following procedural steps are to be omitted. 
 j) Connect the bleed valve and pressure gauge to the drain port of the system's heat transfer loop and 
connect the isolation valve and hydraulic pressure source, using the manufacturer's stated heat transfer 
fluid, to the fill port of the heat transfer loop. 
 k) Fill the heat transfer loop of the system using the hydr aulic pressure source and bleed all air, as possible, 
out of the loop through the bleed valve at the drain part of the top of the collector array. 
 
I) Apply a hydraulic pressure equal to 1.5 times the manufacturer's stated maximum individual working 
pressures. 
 m) Isolate the pressure source by closing the isolation valve and record the readings of the pressure gauge 
at the beginning and end of the next 15 min interval. 
 
n) Release the system pressure through the bleed valve and record any visible permanent deformation and 
heat transfer fluid leakage from system components and interconnections. 
 
5.3.5 Reporting requirements 
 
Report the maximum test pressures applied, the pressure readings at the beginning and end of the 15 min 
 
Test intervals and any visible permanent deformation or leakage from system components and interconnections. Note if the applied test pressures are lower than 1.5 times the manufacturer's stated 
maximum working pressure. 
 
5.4 Water contamination 
 
See EN 1717. 
 
5.5 Lightning protection 
 
Annexes E and F give information to assist manufacturers in meeting the requirements given in IEC 61024-1. PUBLIC REVIEW DRAFT, SEPTEMBER 2008KS 1852-2:2008 
© KEBS 2008 — All rights reserved 7  
5.6 Safety equipment 
 
5.6.1 Safety valves 
 
Check the system documentation to verify that each collector circuit or group of collector circuits is fitted with 
at least one safety valve. 
 Check the specification of the safety valves, whether the materials conform to requirements given in 4.4.1 of 
KS 1852-1. 
 
Check whether the size of the safety valve is correct in conformity with the requirements given in 4.4.1 of KS 
1852-1.  
Check whether the temperature of the heat transfer medium at the release pressure of the safety valve 
exceeds the maximum allowed temperature of the heat transfer medium. 
 
To check the applicability of the spec ified maintenance frequency of a ther mostatic valve, the ageing test for 
thermostatic valves should be carried out, as described in Annex D. 
 
5.6.2 Safety lines and expansion lines 
 
Check the system documentation to verify that safety and expansion lines, if any, cannot be shut-off. 
 
Check the internal diameter of the expansion line, if any, with respect to the requirements given in 4.4.2 of KS 
1852-1.  
Check the system documentation to verify that the expansion line and the safety line, if any, are connected 
and laid in such a way that any accumulation of dirt, scale or similar impurities are avoided.  
5.6.3 Blow-off lines 
 
Check the hydraulic scheme and system documentation to verify that the blow-off lines, if any, conform to 
requirements given in 4.4.3 of KS 1852-1.  5.7 Labelling 
 
Check the Marking plate or Label of the solar heating sy stem and examine if all items of the labelling list are 
completed (as specified in 4.7 of KS 1852-1). 
 
5.8 Thermal performance characterization   
 
5.8.1 Introduction 
 
In this clause the methods for performance testing are described. The thermal performance of the system 
shall be characterized as described in 5.8.2 and presented as specified in 5.8.3  
NOTE The performance of a solar heating system depends on the individual installation and actual boundary conditions. With rega rd 
to the heat losses of the store besides deficits in the therma l insulation, badly designed connections can increase the heat lo ss capacity 
rate of the store due to natural convection that occurs internal ly in the pipe. In order to avoid this effect the connections o f the pipes 
should be designed in such a way that no natural convection insi de the pipe occurs. This can e. g. be achieved if the pipe is d irectly going 
downwards after leaving the store or by using a siphon. 
 
5.8.2 Test procedure 
 
One of the following test methods shall be used, as described in Table 2. 
 
a) Test method in accordance with ISO 9459-2. PUBLIC REVIEW DRAFT, SEPTEMBER 2008KS 1852-2:2008 
8 © KEBS 2008 — All rights reserved  
This test method may be applied on "solar only" or "preheat systems". 
 
b) Test method in accordance with ISO 9459-5. This test method may be applied on all types of systems. 
 
Table 2 — Selection of the performance test method 
 
Test method  Solar-plus-supplementary systems *) Solar-only and preheat systems
ISO 9459-2 (CSTG) 
 No 
 Yes 
 
ISO 9459-5 (DST) Yes Yes 
 
NOTE 1 Some systems have allowances for variations in the installation instructions that may affect the performance of the syst em. In 
cases where the circumstances are not uniquely defined by the R eference Conditions given in Annex B, the most unfavourable 
conditions should be chosen for testing and reporting of the system performance. For example, systems without forced circulatio n should 
be tested with the lowest position of the storage above the co llector and the longest pipe length between collector and storage  specified 
by the manufacturer. 
 
NOTE 2 In October 1999, the EU-SMT project team "Bridging the Gap" reported on the comparability between CSTG (ISO 9459-2) and 
DST (ISO 9459-5) and conversion factors were successfully established. The relation between the performance predictions of both  test 
methods is given by: 
 
CSTG a DST ) ( Q a Q σ±=  
 
The 'a-values' are represented in Table 3: 
 
Table 3 — Parameter a values for different load volumes 
 
Type of system  Condition a σa 
Forced circulation 
Thermosyphon system  
ICS system Vload≥ V store a 
All Vload 
All V load 1.004  
1.056  
1.037 0.004 
0.004  
0.003 
a In the case V load < V store (forced circulation systems), the determined 'a-values' are higher. This indicates a stronge r 
tendenc y for overestimation of the DST test method.
 
5.8.3 Prediction of yearly  performance indicators 
 
5.8.3.1 General 
 
NOTE In the following, performance indicators for solar heating systems for hot water preparation only are specified. The text of these 
paragraphs is identical for this standard and for Custom Built Systems (KS 1855-2). Performance indicators for space heating sy stems 
are presently excluded, since there is not yet enough experience avai lable. This is a preliminary step for the standardization of this 
procedure. After enough experience has been gained, also the performance indicators for space heating systems will be elaborate d. 
 
Uniform reference conditions for the calculation of the performance are specified in the identical Annex B of 
this standard or Annex A of KS 1855-2. For these conditions, the following performance indicators shall be 
derived from the performance test results: 
 
For "solar-plus-supplementary systems"  
a) the net auxiliary energy demand Q
aux, net  
 
b) parasitic energy Qpar 
 
For "solar-only" and "preheat systems": 
 
c) the heat delivered by the solar heating system QL 
 PUBLIC REVIEW DRAFT, SEPTEMBER 2008KS 1852-2:2008 
© KEBS 2008 — All rights reserved 9 d) the solar fraction fsol 
 
e) the parasitic energy, Qpar, if any 
 
5.8.3.2 Calculation of the net auxiliary energy demand for solar-plus-supplementary systems 
 
Calculate the yearly ne t auxiliary energy demand Qaux,net  directly by computer simulation (long term 
performance prediction) as specified in 5.8.2 of this standard (for Factory Made systems) or 7.5.1 of KS 1855-
2 (for Custom Built Systems). Additional indication on the quantities entering the energy balance of a one-
store solar-plus-supplementary heating system may be found in Figure 1. 
 
If a solar-plus-supplementary system cannot meet the heat demand to such a degree that the energy delivered to the user is less than 90 % of the yearly heat demand, this shall be stated in the test report. 
 
NOTE The energy delivered to the user can be less than the heat demand for example when the power of the auxiliary heater is no t 
sufficient or when strong mixing occurs in the store during draw-offs. 
 
Key 
1 Collector 
2 Pump 
3 Store 
4 Auxiliary heater 
5 Control unit 
6 Cold water 
 
Figure 1— Energy balance for one-store solar-plus-supplementary systems (example) 
 
5.8.3.3 Calculation of the solar fraction for solar-only and preheat systems 
 Compute the system energy balance on a yearly basis. This includes the following energy quantities (see Figure 2 and Figure 3), calculated using the reference data and conditions given in Annex B of this standard 
or Annex A of KS 1855-2. 
 Q
d heat demand; 
 
QL heat delivered by the solar heating system (load) 
 
Qpar parasitic energy (electricity) for pump and controls 
 PUBLIC REVIEW DRAFT, SEPTEMBER 2008KS 1852-2:2008 
10 © KEBS 2008 — All rights reserved The parasitic energy Qpar shall be calculated according to 5.8.3.4. 
 
NOTE 1 The reference locations for calculating the load QL are the store ports or the load-side heat exchanger ports, if provided. The 
reference temperature for calculating the loads is the cold water temperature. Heat losses of the circulation line are not incl uded in the 
loads. 
 
NOTE 2 According to ISO 9488, a solar preheat system is a solar system to preheat water or air prior to its entry into any other type of 
water or air heater. This water or air heater is not part of the solar preheat system itself. Hence, for this type of system th e energy 
delivered by the solar heating system QL is calculated at the outlet of the solar heating system and the store heat loss QI is the heat loss 
of the solar store itself (see Figure 3) 
 
NOTE 3 The yearly heat demand is calculated using the load volume, cold water temperature and the desired temperature for hot water 
as specified in Annex B. 
 
Key 
1 Collector 2 Pump 3 Store 
4 Control unit 
5 Cold water 
 
Figure 2 — Energy balance for solar-only systems 
 PUBLIC REVIEW DRAFT, SEPTEMBER 2008KS 1852-2:2008 
© KEBS 2008 — All rights reserved 11 
 
Key 
1 Collector 2 Pump 3 Solar store 
4 Auxiliary heater 
5 Control unit 
6 Cold water 
7 Solar preheat system 
8 Series connected auxiliary heating system 
 
Figure 3 — Energy balance for solar preheat systems 
 
Calculate the solar fraction, fsol by using the definition of ISO 9488. 
 
Solar fraction fsol: The energy supplied by the solar part of a system divided by the total system load ( Qd = 
heat demand). 
 
fsol = QL/Qd 
 
5.8.3.4 Calculation of the parasitic energy 
 
Calculate the yearly parasitic energy needed by pumps, controllers etc, in conformity with 4.6.3 h) 3) of KS 
1852-1. 
 5.8.3.5 Presentation of performance indicators 
 
The results from 5.8.3.2 to 5.8.3.4 shall be presented for the load volume(s) as specified in Annex B or Annex 
A of KS 1855-2. For Factory Made Systems, the reporting form given in Annex A shall be used, for Custom Built systems the table given in 7.6 of KS 1855-2 shall be used. 
 
 PUBLIC REVIEW DRAFT, SEPTEMBER 2008KS 1852-2:2008 
12 © KEBS 2008 — All rights reserved 5.9 Ability of solar-plus-supplementary systems to cover the load 
 
5.9.1 General 
 
The test described in this clause shall be carried ou t in order to ensure that the solar-plus-supplementary 
system is able to cover the maximum daily load without solar contribution. If recommended by the manufacturer, this test can be performed for a daily load higher than the maximum daily load related to the 
reported performance prediction (5.9.3). If the system  fails to cover the maximum daily load, this shall be 
stated in the test report together with the results of the performance prediction related to this maximum daily 
load. The test shall be repeated  for a lower maximum daily load. 
 The ability of the system to cover the maximum daily load shall be determined for the boundary conditions given in 5.9.2 and 5.9.3. 
 
For systems with auxiliary heater, which are tested in accordance with the test method given in ISO 9459-5 (see 5.9.2), the ability of the system to cover the ma ximum daily load without so lar contribution shall be 
determined either by the test described in 5.9.4 or by means of numerical simulations as described in 5.9.5.  
5.9.2 Boundary conditions for auxiliary heating 
 
The auxiliary heater shall be mounted and operated during the test in accordance with the settings in Annex B 
for the yearly performance prediction.  
In the case of an emergency heater the apparatus shall be made fully operational in accordance with the 
manufacturers specifications.  
When several types of heating devices can be installed, the heating device with a heating power fitted for the maximum "daily load volume" shall be used. The manufacture r shall in this case select the appropriate type of 
heating device.  For systems with auxiliary heating by means of heated water (e.g. directly or with an immersed heat exchanger inside the store) the "flowrate through auxiliary heat exchanger" shall be as stated in Table B.1. 
 The following specificatio ns shall be reported: 
 
⎯ the control setting for the temperatur e of the integrated auxiliary heater; 
 
⎯ the type of control, if available the serial number of the device and if applicable the setting of the 
hysteresis; 
 
⎯ the power of the electrical auxiliary heating element or the thermal power delivered to the store as 
applicable; 
 
⎯ if applicable the flowrate through the heating device. 
 
5.9.3 Boundary conditions for daily load 
 
The "maximum daily load conditions" are characterized by: 
 
⎯ volume, as being the highest daily load volume for which the yearly performance is reported (Table B.1); 
 
⎯ flowrate, in accordance with Table B.1; 
 
⎯ cold water temperature, in accordance with the lowest value in Table B.4. 
 PUBLIC REVIEW DRAFT, SEPTEMBER 2008KS 1852-2:2008 
© KEBS 2008 — All rights reserved 13 If the cold water inlet temperature during the test in accordance with 5.9.4 differs from the minimum cold 
water inlet temperature in accordance with Table B.4, the draw-off flow rate shall be adjusted in order to 
perform a discharge with the same power as calculated with the defined settings. 
 
One "daily load cycle" consists of the following draw-offs based on the cold water temperature (the cycle 
starts at t o): 
 
⎯ at t = (t0 + 12) h withdraw of 40 % the daily load volume; 
 
⎯ at t = (t0 + 17) h withdraw of 20 % the daily load volume; 
 
⎯ at t = (t0 + 22) h withdraw of 40 % the daily load volume;  
 
If repeated tests are necessary the cycle starts again at 24 h after the last t0. 
 
NOTE Some kinds of stores with an integrated domestic hot water heat exchanger where the flow inside the store depends on certa in 
thermosiphonic effects, sometimes require a certain temperature in the lower part of the store in order to reach their full per formance with 
respect to hot water preparation. In this case it is recommended to repeat the daily load cycle several times. 
 
5.9.4 Determination of the ability to cover the maximum daily load by means of testing the system 
 
The system shall be mounted, fully operational, but with: 
 
⎯ the collector circuit disabled or the collector covered in such a way that there is no contribution from the 
solar collector to the store; 
 
⎯ the mixing valve installed, and set as described in the product specifications, only if it is an integral part 
of the system. At the beginning of the test at least three store volumes shall be withdrawn while the 
auxiliary is disabled. 
 
After this initial conditioning ( t = t0) the auxiliary heating is set into oper ation. Discharges in accordance with 
the daily load cycle as described in 5.9.3 shall be performed. 
 
During each draw-off the temperature of the hot water drawn from the store and the thermal power 
discharged from the store shall be measured and recorded. 
 The test with a duration of one daily load cycle is considered as valid, if during 95 % of the draw-off time the 
hot water temperature does not drop below 45 °C. 
 
5.9.5 Determination of the ability to cover the maximum daily load by means of numerical 
simulations 
 
For the determination of the ability to cover the maximu m daily load by means of numerical simulations the 
model given in ISO 9495-5, with the boundary conditions described in 5.9.2 and 5.9.3 shall be used. 
 
The calculation procedure for the determination of the ability to cover the maximum daily load (without solar 
contribution) by means of numerical simulations is in principle similar to the test procedure described in 5.9.4. 
 
During the calculation process the sola r irradiation shall be set to zero. 
 The power for the heating element used in the DST-model shall be determined as the mean value of the 
measured power delivered to the store during the first he ating up of the auxiliary part within the test sequence 
S
aux. The test with a duration of one daily load cycle is considered as valid, if during 95 % of the draw-off time 
the hot water temperature does not drop below 45 °C. 
 
5.10 Reverse flow protection 
 
Visual inspection shall be performed on the existence of a check valve or other provisions. PUBLIC REVIEW DRAFT, SEPTEMBER 2008KS 1852-2:2008 
14 © KEBS 2008 — All rights reserved  
5.11 Electrical safety 
 If the system contains any electrical device, these shall be tested in accordance with IEC 60335-1 and IEC 
60335-2-21. 
 PUBLIC REVIEW DRAFT, SEPTEMBER 2008KS 1852-2:2008 
© KEBS 2008 — All rights reserved 15  
Annex A 
(normative) 
 
Thermal performance presentation sheet 
 
Name and type    :………………………………  Factory Made/Custom Built System a 
 
Derived from test report   :                                                                                                         
By test institute    :                                                                                                         
This table filled in by   :                                                                                                         
Date     :                                                                               
Test method used   :Factory made Systems ISO 9449-5a 
     :Custom Built System: KS 1855-2a 
Integrated auxiliary heater   :Electric / Indirect / Direct Gas / None / Other.                                
 
NOTE .In case of solar heating systems with emergency heaters, instructions should be issued that this emergency 
heater shall only be used for emergency heater purposes. 
a Select appropriate option 
 
Figure A.1 — Thermal performance presentation sheet 
 
 
Table A.1 — Presentation of the system performance indicators for solar-plus-supplementary 
systems 
 
Performance indicators for solar-plus-supplementary systems on annual base for a demand 
volume of ....... L d-1 
 
 
Location 
(latitude) 
 Qd 
MJ 
 Qaux,net   
MJ 
 Qpar 
MJ 
 
Stockholm 
(59.6° N) 
 —  
  
 
Wurzburg 
(49.5° N) 
 — 
  
   
Davos 
(46.8° N) 
 — 
  
   
Athens 
(38.0° N) 
 — 
     
a 
— 
       
 
a For a location free to choose 
 
 PUBLIC REVIEW DRAFT, SEPTEMBER 2008KS 1852-2:2008 
16 © KEBS 2008 — All rights reserved  
Table A.2 — Presentation of the system performance indicators for solar-only and solar preheat 
systems 
 
Performance indicators for solar-only and solar preheat systems on annual base for a demand volume 
of....... Ld-1 
 
Location 
(latitude) 
 Qd 
MJ 
 QL 
MJ 
 fsol 
% 
 Qpar 
MJ 
 
Stockholm 
(59.6° N) 
  
— 
  
     
Wurzburg 
(49.5° N) 
 — 
  
     
Davos 
(46.8° N) 
 — 
       
Athens 
(38.0° N) 
 •— 
       
a 
—  
       
 
a For a location free to choose 
 
  PUBLIC REVIEW DRAFT, SEPTEMBER 2008KS 1852-2:2008 
© KEBS 2008 — All rights reserved 17  
Annex B 
(normative) 
 
Reference conditions for performance prediction 
 
B.1 General 
 
The conditions given in Table B.1 shall be used when calculating, reporting or comparing the performance of 
a system, either from a test or from a computer simulation. These conditions should also be applied to the 
system during any system performance test, if not specified otherwise.  
NOTE Except the specification in respect of the status of the auxi liary heater for solar-plus-supplementary systems (see Table A.1 in 
KS 1855-2), the following reference conditions are identical for testing and simulating of Factory Made Systems in this standar d and 
Custom Built Systems in KS 1855-2. 
 
For systems tested according to ISO 9459-2, the Long Term Performance Prediction, will be in agreement 
with the reference conditions of this annex provided that the following changes in the calculation procedure 
are implemented: 
 
Changes in Clause 9 of ISO 9459-2:1995 (pages 21, 22, 23 and 24), Step 3 (Energy drawn off):  
Calculations for Day 1: 
 
Q
c(1) is calculated according to: 
 
∫′
=V
c dVVf Q Q
0)()1( )1(  
 
where V’ is determined by two conditions: 
 
Qc(1) ≤ VloadρwCpw(tload - tmain) and   V’ ≥ Vload 
 
Calculations for Day 2 and subsequent days: 
 
Qc(2:part1) is calculated according to: 
 
Qc(2:part1) = Q(2: part1) ∫′V
dVVf
0)(  
 
and Qc(2:part 2) is calculated according to: 
 
Qc(2: Part 2) = Q(2:Part 1) ∫′V
dVVg
0)(  
 
The value V‘ is determined when the total energy extracted is calculated according to: 
 
Qc(2) = Qc(2: part 1) + Q c(2: part 2) ≤ VloadρwCpw(tload – tmain)    and    V’ ≤ Vload 
 
The calculations done according to this procedure give lower values than with one load volume extracted 
every day, but will give higher values than with the consideration of a minimum load temperature. 
 
 PUBLIC REVIEW DRAFT, SEPTEMBER 2008KS 1852-2:2008 
18 © KEBS 2008 — All rights reserved  
Table B.1 — Reference conditions for performance presentation 
 
Reference condition Value Remarks
 
SYSTEM 
Collector orientation South  
Collector Tilt Angle 45° 
 For testing, (45 ± 5)° if not fixed for the system or 
specified by the manufacturer. 
Total length of collector circuit 20 m (10 m + 10 m) If piping is not delivered with the system or specified 
by the manufacturer. 
Pipe diameter and insulation thickness of collector circuit See B.2 If piping is not delivered with the system or specified 
by the manufacturer. 
Location of collector circuit pipes Indoor, for systems with store 
situated indoors; Outdoor, for systems with store 
situated outdoors As far as possible at the test rig 
Store ambient temperature 15 °C For systems where the store is located outside, the 
ambient temperature from the climate data shall be 
used. 
For systems with indirect (hydraulic) auxiliary heating: Power to be 
applied on auxiliary heat exchanger (100 ± 30) W per litre of store 
volume above the lowest end of heat 
exchanger If the auxiliary heater is not delivered with the system 
and no restrictions have been given in the 
documentation. 
The auxiliary heater shall be modelled as an ideal heat 
source with no heat capacity and constant heating power. 
Flowrate through auxiliary heat 
exchanger The flowrate through the heat exchanger shall be chosen such that the temperature difference between the inlet and outlet of the auxiliary heat exchanger is (10 ± 2) K under 
steady state conditions, unless specified otherwise by the manufacturer. 
For systems with electrical auxiliary heating: Power of electrical element  If an electrical element is normally delivered with the system or specified by the manufacturer, this element shall be used. Otherwise, (25 ± 8) W per litre of store volume above the electrical element. 
Temperature of integrated auxiliary 
heating 52.5 °C (minimum temperature of hysteresis) Or a higher temperature, if recommended by the manufacturer 
 
CLIMATE 
Reference locations Stockholm, Wiirzburg, Davos, 
Athens In the reporting form, the performance of a different location of choice may also be given. 
Climate Data For Stockholm: CEC Test Reference Year; for Davos, Wurzburg and Athens: Test Reference 
Year. 
 HEAT LOAD 
Daily load pattern For all systems: 100 % at 6 h after solar noon For testing, the load patterns shall be as 
specified in the test procedure. 
Cold water supply temperature See B.3 
 For testing, the temperature shall be as specified in the test procedure 
Desired (mixing valve) temperature 45 °C If the daily or yearly loads are calculated in terms of 
energy, this energy shall be calculated using the cold water supply temperature and the desired 
temperature. 
Daily load volume The load volumes in litres per day shall be chosen from the following series: 50 l/d, 80 l/d, 
110 l/d, 140 l/d, 170 l/d, 200 l/d, 250 l/d, 300 l/d, 400 l/d, 600 l/d. If larger loads are required, 
the series may be extended by repeatedly multiplying by V2 and rounding to the nearest multiple of 10. The manufacturer shall give a design load for the system. The nearest value given in the 
above series shall be used, as well as the next lower and higher values. It is recommended 
to use all lower and higher values from the series, which lie between 0,5 times and 1,5 times 
the design load. 
 
NOTE Fixed load volumes have been chosen to facilitate comparison of the performance of different systems.  For testing, the load volumes as specified in the test procedures shall be used. 
Draw-off flow rate 101/min If the maximal design draw-off flow rate of the system 
is less than 10 l/min, the maximum design draw-off 
rate of the system shall be used. 
 
 PUBLIC REVIEW DRAFT, SEPTEMBER 2008KS 1852-2:2008 
© KEBS 2008 — All rights reserved 19 B.2 Pipe diameter and insulation thickness 
 
If the pipe and insulation for the collector circuit are delivered with the system, or the pipe diameter and the 
insulation thickness to be used for the collector circuit are clearly specified in the installation manual for the 
system, the delivered hardware or the specified values shall be used. 
 
When piping and insulation are not delivered with the system or clearly specified, the pipe diameter, 
thickness and insulation thickness given in Table B.2 shall be used for forced-circulation systems. 
 When piping and insulation are not delivered with the system or clearly specified, the pipe diameter, 
thickness and insulation thickness given in Table B.3 shall be used for thermosiphon systems. 
 The material for the collector circuit piping shall be co pper, unless specified otherwise in the installation 
manual.  
B.3 Calculation of cold water temperature at reference location 
 The cold water temperature shall be calculated in accordance with: 
 
ϑcw=ϑaverage  + Δϑamplitsin(2π([Day] – D s) / 365) 
 
where 
ϑcw  is the cold water temperature to be used for performance presentation 
ϑaverage   is the yearly average cold water temperature on reference location 
ϑΔamplit is the average amplitude of seasonal variations on reference location 
[Day]  is the day number of the year is Shift term 
Ds  is Shift term  
 
The yearly average cold water temperature, average amplitude of seasonal cold water temperature variations 
and shift term given in Table B.4 shall be used for the reference locations. 
 
Table B.2 — Pipe diameter and insulation thickness for forced-circulation systems 
 
Flow rate in collector 
circuit 
l/h External pipe diameter 
 
mm Pipe thickness
 
mm Thickness of one layer 
insulation 1 
mm 
<90 10 ±1 1 20 ± 2 
≥90 and ≤140 12±1 1 20 ± 2 
≥140and ≤ 235 15±1 1 20 ± 2 
≥235 and ≤ 405 18 ±1 1 20 ± 2 
≥405 and ≤ 565 22 ±1 1 20 ± 2 
≥565 and ≤880 28±1 1.5 30 ± 2 
≥ 880 and ≤ 1445 35 ±1 1.5 30 ± 2 
≥1445 and ≤ 1500 42 ± 1 1.5 39 ± 2 
>1500 Such that the flow velocity 
is approximately 0.5 m/s. 1.5 Same as internal pipe diameter
1 Based on a thermal conductivity of 0.04 W/m.K ± 0.01 for temperature of 10 °C 
 PUBLIC REVIEW DRAFT, SEPTEMBER 2008KS 1852-2:2008 
20 © KEBS 2008 — All rights reserved  
 
Table B.3 — Pipe diameter and insulation thickness for thermosiphon systems 
 
Collector array 
aperture area 
 
m2 External pipe diameter
 
 
mm Pipe thickness 
  
mm Thickness of one layer 
insulation 
 
mm 
≥1 and < 2 
 15 ± 1 
 1 
 20 ± 2 
 
≥2and < 6 
 18± 1 
 1.5 
 30 ± 2 
 
≥6and < 10 22 ± 1 1.5 39 ± 2 
1 Based on a thermal conductivity of 0.04 W/m.K ± 0.01 for temperature of 10 °C 
 
 
 
Table B.4 — Data for calculation of the cold water temperature at the reference locations 
 
Reference location ϑaverage  
°C ϑΔamplit 
°C Ds 
d 
Stockholm 8.5 6.4 137 
Wurzburg 10.0 3.0 137 
Davos 5.4 0.8 137 
Athens 17.8 7.4 137 
 PUBLIC REVIEW DRAFT, SEPTEMBER 2008KS 1852-2:2008 
© KEBS 2008 — All rights reserved 21  
Annex C 
(informative) 
 
Extreme climate test procedure for the assessment of the frost resistance of solar DHW 
systems with outdoor tank 
 
C.1 Indoor test procedure for assessment of the frost resistance of solar DWH systems with outdoor tank 
 
C.1.1 Objective and applicability 
 
The purpose of this test is to determine whether extrem e frost conditions for a certain climate region will damage a 
solar domestic hot water (DHW) system or influe nce the proper functioning of such a system. 
 
The test is applicable to ICS systems and other solar DHW systems with the storage tank placed outdoors, and takes 
into account the connecting piping and freeze protection device (s). It is suited for systems with or without active freeze 
protection devices (like a small internal heater). 
 
C.1.2 Apparatus and mounting of the system 
 
The solar DHW system is mounted in a climate chamber which is large enough to contain the complete system and the 
necessary mounting cons truction, and which is capable of generating th e necessary test conditions with regard to 
temperature, wind speed and irradiation. The lamps to provid e irradiation do not need to ha ve a spectrum similar to the 
solar spectrum, however appropriate measures should be take n to avoid excessive infrared radiation to the solar DHW 
system (for instance, a transparent screen between the lamps and the solar DHW system which absorbs infrared 
radiation and which is cooled by a fan). Installation should be similar to realistic conditions, taking into account the most 
severe conditions that are allowed in the installation manual. 
 
The system should be mounted in accordan ce with the installation instruction. Special attention should be given to the 
following points: 
 
⎯ the mounting and installation of the piping into and from the solar DHW system, including   check valve and 
any freeze protection measures. 
 
⎯ any freeze protection measures required in the installation manual. 
 
⎯ the way the solar DHW system is mounted on the roof.  
 
If installation instruction allow the system  to be mounted on a flat roof, or otherwise in such a way that no thermal 
contact with the indoor climate is esta blished, the system should be mounted in such a way that all components are 
exposed to the cold air temperature in the climate chamber as much as allowed. If however, in accordance with the 
installation instruction, the system may only be integrated in to the roof or otherwise being in contact with the indoor 
ambient air temperature, the system should accordingly be mounted on a test roof. The test roof should be placed at 
the lowest tilt angle allowed in the installation instruction.  Figures C.1 to C.4 give some  examples of mounting, while 
Figure C.5 gives an overview of the test chamber.  
 PUBLIC REVIEW DRAFT, SEPTEMBER 2008KS 1852-2:2008 
22 © KEBS 2008 — All rights reserved 
 
 
Key 
1 SDHW system  
2 Titled roof  
3 Indoor (Attic) temperature ϑi 
4 DHW pipes  Key 
1 SDHW system  
2 Flat roof support  
3 DHW pipes  
4 Flat roof  
Figure C.1 — Solar DHW system mounted in a tilted 
roof  Figure C.2 - Solar DHW system mounted on a flat roof support
 
 
 
 
 
Key 
1 SDHW system  
2 Titled roof  
3 DHW pipes through roof opening  
4 Indoor (Attic) temperature ϑi Key 
1 SDHW system  
2 Closed extension to flat roof  
3 Indoor (Attic) temperature ϑi 
4 DHW pipes through roof opening
 Figure C.3 — Solar DHW system mounted on a tilted 
roof with thermal contact to indoor ambient air
  
Figure C.4 — Solar DHW system mounted on a tilted 
extension of a flat roof wi th thermal contact to indoor 
ambient air  
 PUBLIC REVIEW DRAFT, SEPTEMBER 2008KS 1852-2:2008 
© KEBS 2008 — All rights reserved 23 
 
 
Key 
1 Light source  
2 Infrared absorption screen  
3 SDHW system  
4 Fan  
5 Expansion tank  
6 Transparent mains water tank enables detection of small flows  
7 Safety valve (installed ace. to installers instructions)  
8 Draw-off valve  
9 Check valve  
10 Insulated, climatised test chamber with test roof 
 
  
Pyranometer 
  
Anemometer  
 Fluid thermometer ( ϑ), flow meter ( V) or pressure sensor ( P) 
 Air thermometer 
 
Figure C.5 ―Schematic of test set-up 
 
The water flow rate and volume to the solar DHW system should be measured in the mains water pipe and monitored 
throughout the test. Also the volume of water discharge d through the hot water pipe as well as through freeze PUBLIC REVIEW DRAFT, SEPTEMBER 2008KS 1852-2:2008 
24 © KEBS 2008 — All rights reserved protection devices or safety valves should be measured an d monitored. The measurement equipment should be able to 
detect water volumes at very low flow rates, with an accuracy  of 5 ml. For outlets, like the domestic hot water outlet and 
safety device outlets, this may be done by capturing the water in an open vessel and weighing it. For the mains water 
pipe, a transparent vessel with expansion vessel is recommended; the water fed to the system can then be measured 
by reading the water level. In that case, the expansion vesse l should allow for pressure of the mains water which does 
not differ more than 10000 Pa from usual mains pressure. When necessary, the vessel can be kept at the mains water 
temperature by refilling. 
 
Water pressure sensors should be placed in the mains wate r and outlet pipes, in order to obtain extra pressure 
information during the test, if any freeze protection requ ires electricity or any other external energy source, the 
consumption of energy should be measured throughout the test. It is recommended to include a means of detecting or 
handling excessive leakage during the test in order to protect the climate chamber. 
 
The system is filled with mains water in accordance with th e installation instruction and checked for any leakage. The 
hot water outlet pipe is then shut off, and the cold wate r pipe is kept at mains pressure. The system is energized as 
specified by the manufacturer, includi ng any freeze protection equipment. If the system contains an auxiliary heating 
which plays a role in freeze protection (as specified by the manufacturer), the auxiliary heater is switched on, otherwise 
kept switched off. The temperature of the mains cold wate r at the inlet to the climate chamber is kept at 5 °C. 
 
C.1.3 Test procedure 
 
The test procedure consists of three periods, which are described below in the order they have to be carried out. The 
values of the parameters mentioned in this description are given in C.1.4. 
 
C.1.3.1 Test period l 
 
C.1.3.1.1 General 
 
Test period I consists of n days with low solar irradiation and ambient air temperature to induce ice growth and/or low 
solar DHW system temperatures, simulating averag e values of extreme climate conditions for the climate region 
considered; see C.1.4.1. 
 
The test starts after the system has been filled as describ ed above, the domestic hot water draw-off flow rate has 
been measured and the hot water valve has been shut off. 
 
C.1.3.1.2 Procedure 
 
Conduct the test as follows.  
 
a) Reduce the air temperature of the test cell to ϑa,1 the indoor ambient air temperature to 1,iϑ (if applicable) and 
apply a wind speed level of  vw,1. 
 
b) Condition the system by drawing off at least thre e times the system volume while keeping the mains water 
temperature at (5 ± 1) °C. Keep the system under these temperature and wind conditions for a period of n days ± 1 
h, starting from the above draw-off. 
 
c) During these n days, periodically apply an irradiance level of G sol,1 during a time interval fsol,1. The start of the first 
irradiation period may be chosen within the first 18 h of t he test period. The start of the second irradiation period 
should be (24 ± 1) h after the start of the first irradiatio n period. The third irradiation period should start (48 ± 1) h 
after the start of the first irradiation period, and so on in a daily cycle. 
 
d) During the test 
 
⎯ visually inspect the solar DHW system for leakage or frost damage at least every four days. No water should be 
withdrawn from the system;  
 
⎯ record the pressure read out of the pressure sensors at least every two hours;  PUBLIC REVIEW DRAFT, SEPTEMBER 2008KS 1852-2:2008 
© KEBS 2008 — All rights reserved 25  
⎯ record the moment and quantity of any water consumption or use of electricity or other external sources;  
 
⎯  especially record the consumption of water which is not equaled by corresponding discharge through the outlet pipe 
or any safety device.  
 
e) At the end of period I, visually inspect the solar DHW system for any leakage or frost damage 
 
C.1.3.2 Test period II  
 
C.1.3.2.1 General  
 
Test period II consists of a number of hours with no solar irradiation as well as absolute minimum ambient air temperature and 
maximum wind speed for the climate region considered. 
 
C.1.3.2.2 Procedure  
 
Conduct the procedure as follows: 
 
a) Immediately after test period I, reduce the air temperature to a,2xϑ  and set the wind speed to Vw,2x and 
maintain this condition during t2 h (starting from the moment when the air temperature reaches a,2xϑ ) 
without any irradiation. No water shall be withdrawn from the system. 
 
b) Record the pressure read out of the pressure sensors at least every two hours. 
 
c) record the moment and quantity of any water consumption or use of electricity or other external sources.  
d) Record especially the consumption of water, which is not equalled by corresponding discharge through 
the outlet pipe or any safety device. 
 
e) At the end of period II, open the draw-off valve for (10 ± 1) s and measure the quantity of water drawn off. 
This may be done by accumulating the drawn off water and weighing it. 
 
When this tapping shows that the domestic hot water line of the system is not blocked by ice, the test 
period III is not necessary. 
 
NOTE Indications for possible pressure build-up in the system are the following: 
 
⎯ ice formation blocking the domestic hot water line (as indicated by no or very low water flow rate during the final draw-off);  
 
⎯ the pressure relief valve was frozen during the test. In many systems, the pressure valve will start leaking during the test 
periods I or II, to release the volume increase caused by ice formation in the systems. When at later stage, i.e. after several  
daily cycles, the pressure valve stops leaking, this is an indi cation of the valve being blocked by ice. A further indication i s 
pressure build-up beyond the release pressure of the pressure relief valve, registered by one of the pressure sensors. 
However, it is also possible that an ice block is located between the system and the sensor. 
 
If ice is blocking the domestic hot water line or the pr essure relief valve is blocked, there is a possibility of 
pressure build-up in the solar DHW system, and the test period III is recommended to investigate whether 
repeated pressure build-up could damage the system. 
 
f) If period III is carried out, visually inspect the solar DHW system for any leakage or frost damage 
immediately after period II. During this inspection, the temperature in the test chamber should not rise 
more than 5 K above the temperature a,2xϑ , for a period of no longer than 1 h. Then immediately (see 
C.1.3.3.2 a)) continue with test period III. 
 
g) If period III is not carried out, withdraw at least three times the system volume while keeping the mains 
water temperature at (5 ± 1) °C. Record the flow rate and the temperature of the drawn off water during PUBLIC REVIEW DRAFT, SEPTEMBER 2008KS 1852-2:2008 
26 © KEBS 2008 — All rights reserved this draw-off. Again visually inspect the solar DHW system for any leakage, frost damage or permanent 
deformation. 
 
C.1.3.3 Test period III 
 
C.1.3.3.1 General 
 
Test period III consists of a 7-day period that simulates daily cycles of frost and defrost. The goal of this test 
is to establish a cumulative effect of cycles of water freezing, expanding and thereby possibly deforming the system, then thawing (during which some extra water could be consumed by the system to compensate the 
decrease in volume of the melted water), and then freezing again. 
 
C.1.3.3.2 Procedure 
 Conduct the procedure as follows:  
a) Start test period III within 2 h after the end of test period II, during which time the temperature in the test 
chamber should not rise more than 5 K above the temperature 
a,2xϑ . 
 
b) Set the wind speed to Vw,3 and start applying the following daily cycle to the system. 
 
c) In the first period with length fsol,3, raise the temperature to a,3xϑ  within the first hour and apply a solar 
irradiance level of G sol,3 in the plane of the solar DHW system cover. 
 
d) In the second period with length (24 – tsol,3) h, lower the temperature to a,3xϑ  within the first hour and 
without applying irradiance. 
 
e) Repeat the steps a) to d) 7 times and continue with f).  
f) At the end of period III,  
⎯ visually inspect the solar DHW system for any leakage or frost damage. 
 
⎯ withdraw at least three times the system volume while keeping the mains water temperature at (5 ± 
1) °C. 
 
⎯ record the flow rate and the temperature of the drawn off water during this draw-off. 
 
⎯ again visually inspect the solar DHW system for any leakage, frost damage or permanent 
deformation. 
 
C.1.4 Test conditions 
 
C.1.4.1 General 
 
C.1.4.2 to C.1.4.4 describe procedures to obtain the test conditions from local weather data. In C.1.4.5, the test conditions are given for the climate region of the Netherlands. 
 
All test conditions are determined from a series of weather data, which includes extreme weather conditions 
for a representative location. The series should consist of weather data, which contain the five most severe 
cold waves ever; 10 days before and 10 days after each cold wave period should be included. If these data 
are not available, a representative weather data file of at least 10 consecutive years should be taken. In this case, the specified penalties as given apply. PUBLIC REVIEW DRAFT, SEPTEMBER 2008KS 1852-2:2008 
© KEBS 2008 — All rights reserved 27  
C.1.4.2 Determination of the test conditions for period I 
 The conditions for test period I are represented by: 
 
H
sol,1 total daily diffuse solar irradiation, in MJ/m2; 
 
Gsol,1 corresponding solar irradiance during a specific time interval fv in W/m2; 
 
a,1ϑ ambient air temperature applied to the parts of the solar DHW system that would normally be 
located outdoors, in °C; 
 
Vw,1 wind speed, in m/s; 
 
i,1ϑ indoor ambient air temperature applied to the parts of the solar DHW system that would normally 
be located indoors, in °C; 
 
n length of the period, in d; 
 
tsol,1 irradiation period, in h. 
 
The quantities n, Hsol,1, Gsol,1, a,1ϑ, Vw,1, i,1ϑ and tsol,1 are determined from the climate data described in 
C.1.4.1 in accordance with the following consecutive steps. In consultation with the manufacturer, more 
severe conditions may be chosen, which should then be reported with the test result. 
 a) Search all possible periods of n consecutive days in the climate data set, with the average ambient air 
temperature below zero for each day in the period and period length n = 7d, 8d, 9d, ..., 19d, 20d and 21 
d. For each period, determine hourly values of the quantity ― H
sol,1/ i,1ϑ and the average value of that 
quantity. 
 
Detect the absolute minimum of all averaged — Hsol,1/ i,1ϑ values found under a), and the date and length n 
of the corresponding period. 
 
c) For this period, calculate the average values of the irradiation, temperature, duration of the daylight 
period and wind speed to obtain, Hsol,1, i,1ϑ, tsol,1 and Vw,1 respectively. 
 
d) If weather data from an arbitrary decade is used, penalty p,1ϑ should be applied to correct a,1ϑ for more 
extreme temperatures than found in the decade investigated. The penalty is a summation of the following 
temperature differences: 
 
⎯ Temperature difference between the minimum n-days average temperature value of the decade 
considered and the average temperature value of the most severe cold wave in the region 
considered. 
 
⎯ Temperature difference correction fo r nightly radiation as the infrared radiation in the test facility is 
less than for real outdoor conditions. 
 
e) The solar irradiance G sol,1 to be used is calculated from the following equation: 
 
Gsol,1 = (106 /3600) × τsnow × τiam × Hsol,1/tsol,1 
 
where: 
 
τsnow = 0.2 the transmission factor of snow layer on the system; PUBLIC REVIEW DRAFT, SEPTEMBER 2008KS 1852-2:2008 
28 © KEBS 2008 — All rights reserved  
τiam = 0.7, the average incidence angle modifier of the system. The value given here is an approximation; 
when a measured value is known this may also be used. This shall be reported with the test results. 
 
f) If the system is mounted in thermal connection to a test roof as described in C.1.2, the air temperature to 
be maintained under the test roof i,1ϑshould be equal to the minimum air temperature specified in the 
instruction manual. If no minimum air temperature is specified, the air temperature under the roof i,1ϑ 
should be equal to (a,1ϑ + 5) K. 
 
These values are used for period I of the freeze protection test.  
 
C.1.4.3 Determination of the test conditions for period II 
 
The conditions for this period are represented by:  
i,2ϑ indoor ambient air temperature, in °C;  
a,2ϑ daily average outdoor ambient air temperature, in °C; 
 
a,2xϑ  minimum hourly ambient air temperature, in °C; 
 
vw,2 wind speed, in m/s; 
 
t2 test period, in h. 
 
From the climate data set as specified in C.1.4.1, find the day with the minimum hourly temperature a,2xϑ . For the same 
day, determine the daily average temperature a,2ϑ. 
 
If weather data from an arbitrary decade is used, penalty p,2ϑ should be applied to correct a,2xϑ  for more extreme 
temperatures than found in the decade (see C.1.4.1) investigated. The penalty is a summation of the following 
temperature differences: 
 
⎯ Temperature difference between the minimum hourly temperature a,2xϑ  and the absolute minimum hourly value in 
the region considered. 
 
⎯ Temperature difference correction for nightly radiation as the in frared radiation in the test facility is less than for real 
outdoor conditions. 
 
Select the absolute maximum hourly average wind speed vw,2 during a period of frost. Calculate the test duration from: 
 
t2 = 24 × a,2ϑ/a,2xϑ  
 
where  
a,2xϑ  is the value without the penalty p,2ϑ described above.  
 
There is no solar irradiation during period II. 
 
If the system is mounted in thermal connection to a test roof as described in C.1.2, the air temperature to be 
maintained under the test roof $ p2 should be equal to the minimum air temperature specified in the instruction manual. If 
no minimum air temperature is specified, the air temperature under the roof i,2ϑ should be equal to (a,2ϑ + 5) K. Again, 
more severe conditions, e.g., a longer test du ration, may be chosen in consultation with the manufacturer. PUBLIC REVIEW DRAFT, SEPTEMBER 2008KS 1852-2:2008 
© KEBS 2008 — All rights reserved 29 C.1.4.4 Determination of the test conditions for period III  
 
The conditions for this period are represented by: 
 
1,3aϑ  indoor ambient air temperature during the irradiation period, in °C; 
 
1,3bϑ  indoor ambient air temperature during the cold period, in °C; 
 
a,3aϑ  outdoor ambient air temperature during the irradiation period, in °C; 
 
a,3bϑ  outdoor ambient air temperature during the cold period, in °C; 
 
Hsol,3 solar irradiation in the plane of the solar DHW system cover, in MJ/(m2.d); 
 
Gsol,3 solar irradiance in the plane of the solar DHW system cover, in W/m2; 
 
vw,3 wind speed, in m/s; 
 
fsol,3 duration of the irradiation period, in h. 
 
Apart from the conditions for period III obtained by the following steps, different conditions in consultation with the 
manufacturer, may be chosen. The conditions us ed should be reported with the test results. 
 
From the climate data set as specified in C.1.4.1, select a consecutive 21-days period around the day with the absolute 
minimum daily average temperature already found in C.1.3.2.  The 21-days period should comprise the 10 days before 
this day, the day itself and the ten consecutive days. 
 
Find in that period the day with the maximum daily average solar irradiation Hsol,3. From that day, also obtain the 
maximum solar irradiance Gsol,3. 
 
Calculate fsol,3 from the following equation:  
 
sol,3 sol,3 sol,3 / ) / ( G H t × = 3600 106 
 
and find, in the 21-days period, the period with length tsol,3 which has the highest average temperature ϑa,3a. Also find, 
in the 21-days period, the period with length (24 - tsol,3) h that has the lowest average temperature a,3bϑ . 
 
The value of vw,3 should be taken equal to vw,1. 
 
If the system is mounted in thermal connection to a test roof as described in C.1.2, the ambient air temperature to be 
maintained under the test roof i,3ϑ should be equal to the minimum air temperature specified in the instruction manual. 
If no minimum air temperature is spec ified, the ambient air temperature under the roof (a,3aϑ  or a,3bϑ ) should be equal to 
the ambient air temperature (a,3aϑ  or a,3bϑ ) + 5K.  
 
C.1.4.5 Test conditions elaborated for specific locations  
 
The procedures given in C.1.4.2 to C. 1.4.4 have b een elaborated for the climate of the Netherlands. The results are: 
 
For test period I: Hsol,1 = 0.3 MJ/(m2.d); G sol,1 = 10 W/m2; a,1ϑ = -9 °C; vw,1 = 5 m/s; n = 14d; t1 = 8.3 h. 
 
For test period II: a,2xϑ  = -30 °C; vw,2 = 10 m/s; t2 = 10 h.  
 
For test period III, no va lues are available yet.  PUBLIC REVIEW DRAFT, SEPTEMBER 2008KS 1852-2:2008 
30 © KEBS 2008 — All rights reserved  
Climate data used involve the years 1961 to 1980. 
 
C.1.5 Results 
 
The following results should be reported: 
 
a) make and model identi fication of the system including aux iliary freeze protection devices fitted. 
 
b) details of installation of the solar DHW system: mounting on or in the test roof, inclination, connections, 
lay-out, insulation of piping, etc. A sketch or photo of the installation should be included. 
 c) location and time span of the climate data considered for determination of the test conditions. 
 
d) all test conditions as determined from the climate data.  
e) record of draw-off flow rate and water temperature during initial conditioning of the solar DHW system at 
the start of period I. 
 
f) volume of water discharged through freeze protection devices.  
g) record of the time of activation of  auxiliary freeze protection devices. 
 
h) record of the water flow rate to the solar DHW system. If the system consumed more water than the 
amount obtained by draw-offs or discharged through free ze protection or other safety devices, this could 
be an indication of internal deformation of the system and it shall be reported. 
 
i) record of consumption of electricity or other external sources by freeze protection devices. 
 
j) results of all visual inspections, includin g any evidence of ice formation or leakage. 
 k) record of water pressure as measured by the pressure sensors. 
 I) volume of water drawn off at the end of period II (only when period III is carried out). 
 
m) record of the draw-off flow rate and water temper ature during the draw-off at the end of period II (if 
possible; only when period III is not carried out). 
 
C.2 Indoor test procedure for assessment of the reliability of solar DWH systems in respect of overheating 
protection 
 
C.2.1 Objective and applicability 
 The purpose of this test is to assess if a solar DHW system is able to withstand extreme overheating 
conditions without being damaged. 
 The test is applicable to solar DHW systems, including connecting piping and overheating protection 
device(s). It is especially suited for systems that do not have an active overheating protection device, however, for systems that do have such a device, the capa bility of that device to protect the system is tested. 
 
C.2.2 Apparatus and mounting of the system 
 
The solar DHW system is mounted in a solar simulator (similar to the solar simulators used for efficiency 
determination of solar collectors), capable of generating the necessary test conditions with regard to 
temperature, wind speed and irradiation (see Figure C.6) . The installation should be similar to realistic 
conditions, taking into account the most severe conditions that are allowed in the installation manual. The 
system slope should be 45°, unless specified otherwise in the installation manual. PUBLIC REVIEW DRAFT, SEPTEMBER 2008KS 1852-2:2008 
© KEBS 2008 — All rights reserved 31  
The system should be mounted in accordance with the installation instructions. Special attention should be given to the 
following points: 
 
⎯ The mounting and installation of the piping to and from the solar DHW system, including check valve and any 
overheating protection measures.  
 
⎯ Any overheating protection measures required in the installation manual.  
 
⎯ The way the solar DHW system is connected to the roof. 
 
 
Key 
1 Solar simulator 
2 SDHW system 3 Safety valve (installed according to installers instructions) 4 Draw-off valve A 5 Heater 6 Pump 
7 Valve C 
8 Non-return 
9 Valve B 
10 Fan 
  
Pyranometer 
  
Anemometer  
 Fluid thermometer ( ϑ), flow meter ( V) or pressure sensor ( P) 
 Air thermometer 
 
Figure C.6 — Scheme of the test set-up PUBLIC REVIEW DRAFT, SEPTEMBER 2008KS 1852-2:2008 
32 © KEBS 2008 — All rights reserved  
The water flow rate into the solar DHW system should be measured in the mains water pipe and monitored 
throughout the test. Also the volume of water discharged through overheating protection devices or safety 
valves should be measured and monitored. 
 
If any overheating protection requires electricity or any other external energy source, the consumption of 
energy should be measured throughout the test. A water pressure sensor should be placed in the mains 
water line. 
 The cold water inlet and the hot water outlet of the solar DHW system are also connected to a circuit 
including a water heater and a pump, which has the purpose of heating up the solar DHW system water 
content at the start of the test period. This extra circuit is fitted with two valves to make it possible to separate the circuit from the normal mains water connection and outlet pipe. Furthermore, a connection is present to 
enable a pressure test to be made on the solar DHW system. 
 The system and test circuit are filled with mains water in accordance with the installa tion instruction. The hot 
water outlet pipe is then shut off.  
C.2.3 Test procedure 
 
Ensure that the solar simulator is switched off. 
 Carry out a pressure safety valve test by gradually raising the water pressure in the solar DHW system to the 
opening pressure of the safety valve. Read the pressure at which the valve opens, and check the system for 
any leakage or damage.  
Restore the system to normal mains water pressure. Energize the system according to the manufacturer instruction, including any overheating protecti on equipment and auxilia ry thermal sources. 
 Connect the water heater circuit to the solar DHW system. Switch on the pump and heat the water in the solar DHW system using the water heater until the water in the solar DHW system reaches (75 ± 2) °C.  
NOTE1 If the solar DHW system is not designed ever to reach a temperature of 75 °C or if it will never reach that temperature d uring 
normal operation, a lower temperature may be chosen. This should be reported with the test results. 
 
Disconnect the water heater circuit and switch the solar DHW system back to mains water supply. Set the 
ambient air temperature in the chamber to i,4ϑ and the wind speed to vw,4. 
 
NOTE 2 i,4ϑ and vw,4 are defined in C.2. 
 
Keep the system under these temperature and wind conditions for a period of 5 days +1 h. During these 5 
days, periodically apply an irradiation of Gsol,4 during a time tsol,4. The daily irradiation should be equal to Hsol,4. 
The start of the first irradiation period may be chosen within the first 6 h of the test period. The start of the 
second irradiation period should be (24 ± 1) h after the start of the first irradiation period. The third irradiation 
period should start (48 + 1) h after the start of the first irradiation period, and so on in a daily cycle. 
 
Record the temperature and amount of the water discharged to prevent overheating. 
 
At the end of the 5-days period, withdraw at least three times the system volume while keeping the mains 
water temperature constant to 1 °C around a value between 10 °C and 20 °C. Record the temperature of the drawn off water during this draw-off. Visually inspect the solar DHW system for any damage or permanent 
deformation. PUBLIC REVIEW DRAFT, SEPTEMBER 2008KS 1852-2:2008 
© KEBS 2008 — All rights reserved 33  
C.2.4 Test conditions  
C.2.4.1 General 
 
In C.2.4.2 a procedure is described to obtain the test conditions from local weather data. In C.2.4.3 the test 
conditions are given for the climate region of the Netherlands. 
 
All test conditions are determined from a series of weather data, which includes extreme weather conditions for a representative location. The series should consist of weather data, which contain the five most severe 
heat waves ever. If these data are not available, a representative weather data file of at least 10 consecutive 
years should be taken. In this case, the specified penalty as given below should be applied.  
C.2.4.2 Determination of test conditions 
 
The conditions for the test are represented by: 
 
i,4ϑ indoor ambient air temperature, in °C; 
 
a,4ϑ outdoor ambient air temperature, in °C; 
 
Hsol,4 5-days average solar irradiation in the plan e of the solar DHW system cover, in MJ/(m2day); 
 
Gsol,4 peak hourly average solar irradiance in the plane of the solar DHW system cover within the 5-days 
period, in W/m2; 
 
vw,4 lowest hourly average wind speed within the 5-days period, in m/s;  
 
tsol,4 duration of the irradiation period, in h. 
 
The quantities H sol,4, G sol,4, tsol,4, a,4ϑ, i,4ϑ and vw,4 are determined from the climate data described in C.2.4.1 
as follows: 
 
a) Select a 5-days period with an average daily irradiation in the plane of the solar DHW system cover H sol,4 
and an average daily temperature a,4ϑ, which holds the absolute maximum product of H sol,4 × a,4ϑ. 
 
b) For the selected period, determine aϑ, xa,ϑ, maxa,ϑ , Hsol,4, Gsol,4 and vw,4 where: 
 
⎯ aϑ is the 5-days average outdoor ambient air temperature, in °C; 
 
⎯ xa,ϑ is the peak hourly average outdoor ambient air temperature within the 5-days period, in °C 
 
⎯ maxa,ϑ  is the peak hourly average outdoor ambient air temperature ever registered, in °C; 
 
Investigate the local weather for maxa,ϑ  as well. 
 
c) Calculate the outdoor ambient air temperature for the test from the following equation: 
 
a,4ϑ = p,4 aϑϑ+  with 
( )xa, maxa, p,4 . ϑϑ ϑ −×=50  
 PUBLIC REVIEW DRAFT, SEPTEMBER 2008KS 1852-2:2008 
34 © KEBS 2008 — All rights reserved where p,4ϑ is the penalty for correction of aϑ for more severe temperatures than those found in the 
decade (see C.2.4.1) investigated: 
 
d) Next, the duration of the irradiation period will be determined. If the solar DHW system to be tested is 
equipped with a TIM (Translucent Insulation Material) one should account for an incidence angle 
dependent transmittance. In that case, the Hsol (not the Gsol) should be corrected with a factor cor sol in 
accordance with the integrated incidence angle modifier (IAM) function of the Tl material: 
 
cor sol = 0.5 I [IAM]( ϕ) × cosϕ 
 
where ϕ is the incidence angle, taken from 0 to 90°. 
 
For a number of TIM's, IAM functions are already known. Typical range of corso| based on the IAM 
function for realistic Tl materials is from 0.90 to 0.75. For a cover having an incidence angle independent 
transmittance, the cor sol is 1.0. Apart from the cover material, the construction of the solar DHW system 
(deep-seated box structures, parabolic mirrors, etc.) may influence the value of the IAM function and 
cor sol. Therefore, it is recommended to use a measured IAM function of the solar DHW system. 
 Taking into account the incidence angle correction, the duration of the daily insolation period is calculated 
by: 
 
t
sol,4 = 277.8 × cor sol × Hsol,4/Gsol,4x. 
 
In order to take into account properties of co mmon solar simulators, a so lar irradiance lower than Gsol,4x 
by at most 20 % can be used to calculate the corresponding tsol,4. 
 e) If the system is mounted in thermal connection to a test roof as described in C.1.2, the ambient air 
temperature to be maintained under the test roof 
i,4ϑ should be equal to the maximum ambient air 
temperature specified in the instruction manual. If no maximum ambient air temperature is specified, the 
ambient air temperature under the roof i,4ϑ should be equal to (a,4ϑ + 5) K. 
 
C.2.4.3 Test conditions elaborated for specific locations 
 
The procedure given in C.2.4.2 has been elaborated for the climate region of the Netherlands. The results are: 
 
a,4ϑ = 27 °C; Hsol,4 = 30 MJ/(m2.day); G a, 4 = 1000 W/m2; vw,4 = 0 m/s; tsol,4 = 8.3 h. 
 
C.2.5 Results 
 
The following results should be reported: 
 a) make and model identifi cation of the system including auxilia ry overheating protection devices  
 
b) details of installation of the solar DHW system: mounting on or in the test roof, inclination, connections, 
lay-out, insulation of piping, etc. A sketch or photo of the installation should be included; 
 c) location and time span of the climate data considered for determination of the test conditions; 
 d) all test conditions as determined from the climate data; 
 
e) volume of water discharged through overheating protection devices and/or safety valves; 
 f) record of the time of activation of auxiliary overheating protection devices; 
 PUBLIC REVIEW DRAFT, SEPTEMBER 2008KS 1852-2:2008 
© KEBS 2008 — All rights reserved 35 g) record of consumption of electricity or other external sources by overheating protection devices; 
 
h) results of all visual inspections, including any evidence of damage or leakage; 
 
i) record of water pressure as measured by the pressure sensor. If during the pressure test the pressure 
valve did not open, or if it opened at a pressure higher than its rated pressure, this should be reported. If the pressure at any time exceeded the pressure rating of the pressure valve, this should also be reported; 
 j) record of the draw-off water temperature during the draw-off at the end of the test. If at any time the water 
temperature exceeded 100 °C, this should be reported. 
 PUBLIC REVIEW DRAFT, SEPTEMBER 2008KS 1852-2:2008 
36 © KEBS 2008 — All rights reserved  
Annex D 
(informative) 
 
Ageing test for thermostatic valves 
 
D.1 General 
 
This accelerated ageing test has the goal to assess t he applicability of the specified maintenance frequency of a 
thermostatic valve, which is used as overheating protecti on valve in a solar heating system. Water of specified 
hardness is used in a cycle of operation and cooling down (c losing). The correct functioning is regularly checked. When 
too large sediments of chalk are observed,  the test duration is recalculated to  an expected period in normal use. 
Therefore, the assumption is made t hat the valve will operate 250 times per year (This number has been estimated 
based on model simulations for Dutch climate with ICS and thermosiphon systems). 
 
D.2 Test arrangement 
 
The test arrangement (see Figure D.1) consists of a mixing  vessel V1 with sufficient volume. The vessel can be filled 
with drinking water through valve 1. Via the open lid, substa nces can be added. The water in the vessel is stirred using 
a stirring device R. In the vessel V1, the water is conditi oned to the required hardness by adding a mixture of calcium 
and magnesium salts. Using a pump H, the conditioned wa ter can be pumped into test vessel V2 where it can be 
heated electrically. On top of V2 there is a connection wher e the valve being tested (labelled T&P) is mounted. A flow 
meter F is used to register the amount of water drained by T&P. 
 
 
 
Figure D.1 — Test arrangement for thermostatic valve test 
 
D.3 Test Procedure 
 
D.3.1  Find out the specified maintenance frequency fm [year-1] of the thermostatic va lve. If the maintenance 
frequency is not specified, assume  a system lifetime of 15 years: fm = 1/15 [year-1]. 
 
D.3.2  Determine the number of cycl es necessary for the test as n = 250 / f m  
 
D.3.3 Start up the test rig: 
 PUBLIC REVIEW DRAFT, SEPTEMBER 2008KS 1852-2:2008 
© KEBS 2008 — All rights reserved 37 a) Rinse V1 with domestic hot water and subsequently fill it. 
 
b) Add magnesium carbonate and calcium sulphate until th e desired hardness is reached. Measure the hardness in 
accordance with ISO 6059. Start the stirring device an d the pump. When refilling the store during the test, the 
amounts of salts to be added may be calculated from the amount of water refilled and the amounts of salts used to 
condition the first store volume. 
 
NOTE 1 The EN 60734 standard specifies procedures to obtain 'hard water to be used for testing the performance of some househol d electrical 
appliances'. This standard is however very labour intensive and expensive. Therefore a simplified method is given here to achie ve the same result. 
 
NOTE 2 At TNO, with drinking water in Delft (hardness 8.5 °D 2) and a volume of V1 of 600 I, 180 gram of magnesium carbonate and 
290.4 gram of calcium sulphate is needed to obtain the desired hardness of about 23  °D. 
 
c) Open valve 2, 3 and 4 to fill V2 with hard water. Close valve 4. 
 
d) Start heating V2 using the electrical heater. At a certain point the valve will open and water will flow from V2 to the 
drain. Cold water is supplied from V1. After a certain time the temperature has dropped sufficiently for the valve 
T&P to close again. 
 
e) When V1 is almost empty, close all valves and shut off the stirring device and the pump, refill V1 with water and 
restart at b). 
 
D.3.4  After every 30th to 35th cycle, check visually if the valve is still functioning. When the valve does not function 
any more after less than n cycles, the number of cycles completed is reported. 
 
D.3.5  After n cycles, report whether the valve is still functioning. Remove the valve and visually inspect the amount 
of sediments on the valve. 
 
D.3.6  If n cycles have been completed with the valve functioning, the specified maintenance frequency is sufficient 
for the valve. Else, convert the number of test cycles to an expected operation period:  
 
expected operating period = number of cycles / 250 [year]. 
 
D.4 Results 
 
Report n, the number of cycles completed and, if applicable, the expected operating period.  
 
                                                 
2) German index of hardness of water. The SI unit is mmol/l; 1 mmol/l = 5.6 °D.  PUBLIC REVIEW DRAFT, SEPTEMBER 2008KS 1852-2:2008 
38 © KEBS 2008 — All rights reserved  
Annex E 
(informative) 
 
Lightning protection test for solar heating systems 
 
E.1 Field of application 
 
This test for lightning protection should be applied only to those parts of Fa ctory Made solar heating systems that are 
normally exposed to outdoor weather/environment conditions. 
 
Systems that contain few or no metallic parts may be excluded from this test.  
 
Test methods for special devices, components and othe r items that may be applied to Factory Made solar heating 
systems or connected to solar heating systems on the roof with LPS installation are not covered by this standard. 
 
The outdoor parts of the system may be considered as "n atural components" on roof constructions and should be 
treated as "natural air termination components" in ac cordance with the relevant lightning protection standards. 
 
NOTE This test is based on IEC 61024-1, modified for the needs of thermal solar heating systems. It is included in this standar d to 
assist the manufacturers in meeting these requirements. 
 
E.2 Purpose  
 
The purpose of this test is to assess the relative resistan ce of the Factory Made solar heating systems and to evaluate 
whether the solar heating system is adequately manufactured to ensure sufficient connections and  protection against 
lightning in case of connecting with a Ligh tning Protection System (LPS) in the building.  
 
The solar heating systems and component s mounted on the roof surface should only be used as a part of the existing 
LPS with the agreement of the structure engineer or the owner. 
 
The connection with LPS cannot guarantee absolute protection to structures, solar heating systems and components 
or persons, but will significantly reduce risk of damage caused by lightning.  
 
E.3 Requirements  
 
The system should conform to the requirements given in IEC 61024-1.  
 
When the water tank is mounted outdoors, the separation distance S t (see E.5.4) should either fulfil  
 
 S t > D t 
 
or there should be at least one connection (bonding cable or strip) between the tank and the outer cover sheet(i.e. in 
front and rear bottom). This bonding cable or strip shou ld have at least the sizes as given in Table F.1, when measured 
in accordance with E.5.5.  
 
 where 
 
Dt is the minimum separation distance (K × K c / K m) x Lt = 0.044 Lt 
 
Lt is the overall length of the tank, in millimetres;  
 
Ki =0.05 
 
Kc = 0.44  
 
Km = 0.50 PUBLIC REVIEW DRAFT, SEPTEMBER 2008KS 1852-2:2008 
© KEBS 2008 — All rights reserved 39  
When the tank is mounted outdoors, the bridging between the tank and the supports should have a total 
contact (connection) area of at least 100 cm2 (overlapping surface bolted or spot welded), when measured in 
accordance with E.5.6. 
 
The bridging between the collectors and supports (as determined in E.5.7) should have a contact 
(connection) surface of at least 100 cm2 (overlapping surface bolted or welded). 
 
E.4 Apparatus 
 
No special apparatus is required except: 
 
⎯ a platform on which the complete solar heating system can be installed in accordance with the 
manufacturer's instructions and 
 
⎯ measuring instruments for distances, etc. (see test procedures below). 
 
E.5 Test procedure 
 
E.5.1 Test conditions 
 
The test is normally carried out on solar heating systems, which are installed in a testing structure in 
accordance with the manufacturer's instructions. 
 
E.5.2 Solar heating system installation  
Install the Factory Made solar water heating system in accordance with the manufacturer's instructions, using 
his material for connections on the testing base stand and between components. Fill up the solar heating system and the close loop, for indirect systems, with water and take care for removing air from all parts 
through the air vents. 
 
E.5.3 Separation distance S
t 
 
Measure the overall length Lt of the tank, in millimetres. 
 Measure the existing separation distance S
t between the tank and the outer metal cover in the front and rear 
bottom. 
 
Calculate the minimum permitted separation distance Dt. 
 
E.5.4 Size of the bonding cable or strip 
 
Check the existence of the above mentioned bonding connections. 
 Measure the size of bonding and calculate the cross sect ion surface (or determine the size from electric cable 
tables). 
 
E.5.5 Bridging between tank and supports 
 
Check if there are bolts or rivets etc. between tank and supports. 
 
Measure and calculate the overlapping surface between these parts. Compare the results with the lower limit of 100 cm
2, overlapping surface. PUBLIC REVIEW DRAFT, SEPTEMBER 2008KS 1852-2:2008 
40 © KEBS 2008 — All rights reserved E.5.6 Bridging between collectors and supports 
 
Check if there are bolts or rivets etc. between collectors and supports. Measure and calculate the overlapping 
surface between these parts. Compare the results with the lower limit of 100 cm2, overlapping surface. 
 
E.5.7 Bridging between collectors and tank 
 
No special inspections. There is sufficient electrical continuity via metal supports. 
 
E.5.8 Connecting terminal with Lightning Protection System (LPS) 
 
Check the existence of the holes and measure the sizes d, I and h. 
 
E.5.9 Metal sheets covering parts of the solar heating system 
 
The electrical continuity check is not covered by this standard, but the relevant standards should be applied. 
Check the thickness of metal sheet. 
 
E.5.10 Heating effects due to lightning currents 
 
The heating effects are considered as negligible. 
 
E.5.11 Mechanical durability due to lightning mechanical loads 
 
The mechanical loads in considered as negligible  
The mechanical loads in the solar components are to o low and the influence on durability and stability is 
considered as negligible. 
 E.6 Report 
 
Report the results of the tests, measurements and calculations in a formal Lightning Protection Testing Sheet 
given in Annex F.  
E.7 Conclusions  
The conclusions include the final evaluation that the Factory Made solar heating system is adequately 
manufactured and capable of connecting with an existing Lightning Protection System (LPS) on the roof of a building. In this way it should be protected against damage due to lighting effects. 
 
Final conclusions are reported and included in the Lighting Protection Testing Sheet. PUBLIC REVIEW DRAFT, SEPTEMBER 2008KS 1852-2:2008 
© KEBS 2008 — All rights reserved 41  
Annex F 
(informative) 
 
Lightning Protection testing sheet 
 
 
Table F.1 — Size of bonding cable 
 
Protection Level 
 
 Cable material 
 Cable cross-section Fc 
mm2 
Large load of lightning Non large load of lightning 
 
I -II -III -IV 
  
Copper (Cu)  
16  
6 
 Aluminium (Al) 25 
 10 
 
 Steel (Fe) 50 16 
 
 
Table F.2 — Size of metal cover sheets 
 
Metal cover sheet 
 Minimum thickness 
mm 
Galvanized steel 
 0.50 
 
Stainless steel 
 0.40 
 
Copper 
 0.30 
 
Aluminium 
 0.70 
 
Zinc 
 0.70 
 
Lead 
 2.00 
 
  PUBLIC REVIEW DRAFT, SEPTEMBER 2008KS 1852-2:2008 
42 © KEBS 2008 — All rights reserved  
Lightning protection testing sheet (Continued) 
 
Laboratory :……………………………………………………………………………………… 
 
No of Test :………………………………………………………………………………………  
Date :…………………………………………………………………………………….. 
 Standard :…………………………………………………………………………………….. 
 Solar heating system No :…………………………………………………………………………………..  
 
Manufacturer  :……………………………………………………………………………………. 
(From manufacturer specifications and by laboratory examination of the sample) 
  
Open system    : Yes   No 
 Closed system : Yes   No 
 
Tank Capacity: ......L  Collector area : m
2 
 
Construction Materials 
Solar Tank  
Tank walls :………………………………………………………………………………….. 
Internal coating :…………………………………………………………………………………… 
Flange and sealings :…………………………………………………………………………………… 
Heating element :…………………………………………………………………………………… Pipes :…………………………………………………………………………………….. 
Heat exchanger :…………………………………………………………………………………… 
Safety devices :…………………………………………………………………………………….. 
Welding/soldering :………………………………………………………………………………….. Other materials :……………………………………………………………………………………  
Solar Collector
 
Absorber pipes :…………………………………………………………………………………... 
Connecting pipes :…………………………………………………………………………………….. 
Sealings :…………………………………………………………………………………….. 
Welding/soldering materials :……………………………………………………………………………………. 
Other materials :……………………………………………………………………………………. 
 Supports
 
Materials :……………………………………………………………………………………. Bolts/rivets/welding :……………………………………………………………………………………. Coating :……………………………………………………………………………………. 
Other materials :……………………………………………………………………………………. 
 
Connecting pipes
 
Pipes :…………………………………………………………………………………… 
Welding/soldering materials :……………………………………………………………………………………. 
Other materials :…………………………………………………………………………………….  PUBLIC REVIEW DRAFT, SEPTEMBER 2008KS 1852-2:2008 
© KEBS 2008 — All rights reserved 43  
1 Special components for connection with IPS:     Yes  No 
2. Test in accordance with other standards :    Yes  No 3. Installation on testing platform  :    Yes  No 4. Length of tank L
t :……. mm 
Separation distance St   :……. mm 
Calculation for Dt :……. mm 
Comparison :          St > Dt   Yes  No 
 :…….  St < Dt   Yes  No 
Need for bonding :    Yes  No 
Number of bonding cable :……..items 
5. Existence of bonding cable  :    Yes  No 
Number of cables or strips  :……… items 
Dimensions of cable ::……… mm Cross section surface F
c  :………. mm2 
Comparison : Fc > …..mm2 (from Table F.1) 
: Fc <……mm2 (from Table F.1) 
 
6. Tank support bridging  
Existence of bolts etc :    Yes      No 
Dimensions of overlapping :………cm.  Surface of overlapping Fov :........ cm2 
 
Comparison : Fov > 100 cm2   Yes  No 
: Fov < 100 cm2    Yes  No 
 
7. Collector supporting bridging 
Existence of bolts etc :    Yes  No 
Dimensions of overlapping :…..cm. Surface of overlapping  Fov  …..cm2 
 
Comparison : Fov > 100 cm2   Yes  No 
: Fov < 100 cm2   Yes  No 
 
8. Existence of 2 Holes  Ö10 :    Yes  No 
Dimensions d = 12 mm: d = ….. mm   Yes  No 
l = 22 mm: l = …… mm   Yes  No 
h = 200 mm h = ….   mm   Yes  No 
 
9. Cover sheet thickness t :……. mm 
Comparison (Table F.2) :  t >….mm   Yes  No 
  : t < …..mm   Yes  No PUBLIC REVIEW DRAFT, SEPTEMBER 2008KS 1852-2:2008 
44 © KEBS 2008 — All rights reserved  
Lightning protection testing sheet (concluded) 
 
 
Laboratory :………………………………………………………………………………………. 
No of Test :……………………………………………………………………………………….. Date :……………………………………………………………………………………….. 
 
Standard :………………………………………………………………………………………..  
Solar heating system No :………………………………………………………………………………………..   
 
 
 
Final Conclusions 
 
  
 
  
  
 
 
 
 
 
Needs for special labe ling-identification: 
 
 
 
 
 
Remarks:  
  
 
 
 
 
Tested by: 
 
 
 
 
Issued by: 
  
 PUBLIC REVIEW DRAFT, SEPTEMBER 2008KS 1852-2:2008 
© KEBS 2008 — All rights reserved 45  
Bibliography 
 
[1] IEC 60734, Household electrical appliances — Performance — Hard water testing  
 
[2] ISO 6059, Water quality — Determination of the sum of calcium and magnesium — EDTA titrimetric 
method  
 
[3] EN 1717, Protection against pollution of potable water in water installations and general requirements 
of devices to prevent pollution by backflow  
 
[4] EN 1991-1-3, Eurocode 1: Actions on structures — Part 1 - 3: General actions — Snow loads   
 
[5] EN 1991-1-4, Eurocode 1: Actions on structures — Part 1 - 4: General actions — Wind actions  
 
[6] KS 1855-1, Thermal solar systems and components — Custom built systems — Part 1: General 
requirements  
 
[7] KS 1855-3, Thermal solar systems and components — Custom built systems — Part 3: Performance 
characterization of stores for solar heating systems  
 [8] IEC 60343, Recommended test methods for determining the relative resistance of insulating materials 
to breakdown by surface discharges  
 [9] IEC 61024-1, Protection of structures against lighting — Part 1: General principles