4 Test conditions 4.1 General The types of hybrid heating appliances considered in this European Standard are variable capacity delivering a variable heating fluid outlet temperature d
Scope of EN 12309
Appliances covered by this European Standard include one or a combination of the following:
— gas-fired sorption chiller/heater;
— gas-fired sorption heat pump
This European Standard applies to appliances designed to be used for space heating or cooling or refrigeration with or without heat recovery
This European Standard pertains to appliances equipped with flue gas systems of types B and C, as defined by CEN/TR 1749, as well as those intended for outdoor installations It is important to note that EN 12309 is not applicable to air conditioners; it exclusively applies to specific appliances with designated flue gas systems.
— integral burners under the control of fully automatic burner control systems,
— closed system refrigerant circuits in which the refrigerant does not come into direct contact with the water or air to be cooled or heated,
— mechanical means to assist transportation of the combustion air and/or the flue gas
The above appliances can have one or more primary or secondary functions (i.e heat recovery - see definitions in EN 12309-1:2014)
In the case of packaged units (consisting of several parts), this standard applies only to those designed and supplied as a complete package
The appliances having their condenser cooled by air and by the evaporation of external additional water are not covered by EN 12309
Installations designed for heating or cooling industrial processes are excluded from the EN 12309 standard It is essential to utilize all symbols provided in this text, irrespective of the language employed.
Scope of this Part 7 of EN 12309
This part of EN 12309 deals particularly with the specific provisions of hybrid heating appliances based on gas-driven sorption heat pumps as defined in Part 1
This European Standard addresses hybrid heating appliances that consist of an encased assembly combining a direct or indirect-fired sorption heat pump for base load and a peak load condensing boiler These appliances feature a single flue system, an electrical supply cable, and a human-machine interface for user interaction The integrated sorption heat pump can operate either intermittently or continuously, utilizing adsorption technology.
The control system of hybrid heating appliances manages the transition between various operation modes, including switching from heat pump mode to mixed operation mode (utilizing both the sorption heat pump and peak boiler) and direct heating mode (using only the peak boiler) This decision is based on several factors, such as the inlet and return temperatures of the heating fluid, the brine temperature entering the indoor heat exchanger of the heat pump, the required supply temperature influenced by outdoor conditions, and the target indoor temperature Additionally, when transitioning to mixed operation mode, the control system determines the degree of mixing according to these parameters.
This document references essential materials that are crucial for its application For references with specific dates, only the cited edition is applicable In the case of undated references, the most recent edition, including any amendments, is relevant.
EN 12309-1:2014, Gas-fired sorption appliances for heating and/or cooling with a net heat input not exceeding
70 kW ― Part 1: Terms and definitions prEN 12309-2:2013 1 , Gas-fired sorption appliances for heating and/or cooling with a net heat input not exceeding 70 kW ― Part 2: Safety
EN 12309-3:2014, Gas-fired sorption appliances for heating and/or cooling with a net heat input not exceeding
EN 12309-4:2014, Gas-fired sorption appliances for heating and/or cooling with a net heat input not exceeding
EN 12309-6:2014, Gas-fired sorption appliances for heating and/or cooling with a net heat input not exceeding
70 kW ― Part 6: Calculation of seasonal performances
For the purposes of this document, the terms and definitions given in EN 12309-1:2014 apply
General
This European Standard addresses hybrid heating appliances that feature variable capacity, which allows for a flexible heating fluid outlet temperature This temperature adjustment is influenced by outdoor ambient air conditions, the designated indoor room temperatures, and the chosen heat sink parameters.
Table 1 outlines the design temperatures for heating, including the coldest outdoor dry bulb temperature for each reference heating season, the designated indoor room temperature (T R), and the balance point or heating limit temperature (T BP) for the three evaluated reference heating seasons under varying climatic conditions.
The EN 12309-6:2014 standard categorizes heating seasons into three types: colder (C), average (A), and warmer (W) The "Average" heating season reflects the weather conditions of Strasburg, while the "Warmer" and "Colder" categories correspond to the climates of Athens and Helsinki, respectively.
Table 1 — Design temperature, indoor temperature and balance point temperatures for the different reference heating seasons
Season Dry bulb temperature conditions
Table 2 presents the design outlet (supply) and inlet (return) temperatures for the building heating network, specifically detailing the heating fluid temperatures as specified in EN 12309-3:2014.
1) This part of EN 12309 is currently being revised
This document references essential materials that are crucial for its application For references with specific dates, only the cited edition is applicable In the case of undated references, the most recent edition, including any amendments, is relevant.
EN 12309-1:2014, Gas-fired sorption appliances for heating and/or cooling with a net heat input not exceeding
70 kW ― Part 1: Terms and definitions prEN 12309-2:2013 1 , Gas-fired sorption appliances for heating and/or cooling with a net heat input not exceeding 70 kW ― Part 2: Safety
EN 12309-3:2014, Gas-fired sorption appliances for heating and/or cooling with a net heat input not exceeding
EN 12309-4:2014, Gas-fired sorption appliances for heating and/or cooling with a net heat input not exceeding
EN 12309-6:2014, Gas-fired sorption appliances for heating and/or cooling with a net heat input not exceeding
70 kW ― Part 6: Calculation of seasonal performances
For the purposes of this document, the terms and definitions given in EN 12309-1:2014 apply
This European Standard addresses hybrid heating appliances that feature variable capacity, which allows for a flexible heating fluid outlet temperature that adjusts based on outdoor ambient air conditions and the designed indoor environment.
(room) temperatures as well as the selected heat sink conditions
Table 1 outlines the design temperatures for heating, including the coldest outdoor dry bulb temperature for each reference heating season, the designated indoor room temperature (T R), and the balance point or heating limit temperature (T BP) for the three evaluated reference heating seasons under varying climatic conditions.
The EN 12309-6:2014 standard categorizes heating seasons into three types: colder (C), average (A), and warmer (W) The "Average" heating season reflects the weather conditions of Strasburg, while the "Warmer" and "Colder" categories correspond to the climates of Athens and Helsinki, respectively.
Table 1 — Design temperature, indoor temperature and balance point temperatures for the different reference heating seasons
Season Dry bulb temperature conditions
In Table 2, the design outlet (supply) and inlet (return) temperatures to and from the building heating network
(heating fluid temperatures from the heating appliance to the heating network and backwards, respectively) are listed as defined in EN 12309-3:2014
1) This part of EN 12309 is currently being revised
Table 2 — Design outlet and inlet temperatures for the different heat sink conditions Reference Heat Sink condition Dry bulb temperature conditions
At least one of the given heat sink conditions in Table 2 shall be declared, upon which the seasonal performance can be evaluated according to this document
The part load ratio for a building at a specific outdoor temperature is the ratio of the building's part load to its design heat load Similarly, the heating appliance part load ratio is defined as the heating capacity required at a given outdoor temperature divided by the appliance's nominal heating capacity.
The accuracy of estimating the seasonal performance of hybrid heating appliances relies significantly on the uniform distribution of reference part load conditions across the building's heat demand curve Defined reference part load ratios for these appliances include 100%, 75%, 60%, 45%, 30%, and 15%.
Due to the 1 K step applied in outdoor temperature according to EN 12309-6:2014, the estimated part load ratios differ from the expected values The nearest part load value is designated as the pivot part load ratio for assessing seasonal performance, as outlined in Table 3.
Table 3 — Reference and pivot part load ratios for the considered reference heating seasons
Pivot PLR for the Reference Heating Seasons
If necessary, at most one more reference test point G between two successive reference test points from A to
F may be added The test conditions should then be linearly interpolated between the two successive standard reference test conditions given in 4.2 and 4.3
The stated nominal heating capacity of the hybrid heating appliance shall always be higher than or equal to the building design load for heating
Gas utilization efficiencies at reference part load conditions can only be used to estimate seasonal performance if the heating capacity at each condition is measured within the deviation limits specified in EN 12309–4:2014.
Inlet temperatures of the indoor heat exchanger
Establishing fixed reference test conditions for part load ratios ensures consistent indoor heat exchanger inlet and outlet temperatures throughout the reference heating seasons Annex A provides a comprehensive method for estimating these temperatures for any part load ratio and reference heating season The estimated inlet and outlet temperatures for the defined reference test part load ratios are detailed in Table 4 for low and medium conditions, and in Table 5 for high and very high temperature heat sink scenarios For further insights, Annex A elaborates on this methodology.
Table 4 — Inlet and outlet temperatures of the indoor heat exchanger for the reference part load test conditions of the low and medium temperature heat sink applications
Low temperature application Medium temperature application
Outlet temperature Inlet temperature Outlet temperature Inlet temperature °C °C °C °C
Table 5 — Inlet and outlet temperatures of the indoor heat exchanger for the reference part load test conditions of the high and very high temperature heat sink applications
High temperature application Very high temperature application
Outlet temperature Inlet temperature Outlet temperature Inlet temperature °C °C °C °C
The part load measurements at the reference test conditions shall follow the inlet temperature method of the
Each reference part load test condition is precisely determined by the part load and the inlet temperatures of both indoor and outdoor heat exchangers The indoor heat exchanger inlet temperatures are specified in Table 4 and Table 5, while the outdoor heat exchanger inlet temperatures are outlined in section 4.3, corresponding to various environmental heat sources.
4.2 Inlet temperatures of the indoor heat exchanger
Establishing fixed reference test conditions for part load ratios ensures consistent indoor heat exchanger inlet and outlet temperatures throughout the reference heating seasons Annex A provides a comprehensive method for estimating these temperatures for any part load ratio and reference heating season The estimated inlet and outlet temperatures for the defined reference test part load ratios are detailed in Table 4 for low and medium conditions, and in Table 5 for high and very high temperature heat sink scenarios For further insights, Annex A elaborates on this methodology.
Table 4 — Inlet and outlet temperatures of the indoor heat exchanger for the reference part load test conditions of the low and medium temperature heat sink applications
Low temperature application Medium temperature application
Outlet temperature Inlet temperature Outlet temperature Inlet temperature °C °C °C °C
Table 5 — Inlet and outlet temperatures of the indoor heat exchanger for the reference part load test conditions of the high and very high temperature heat sink applications
High temperature application Very high temperature application
Outlet temperature Inlet temperature Outlet temperature Inlet temperature °C °C °C °C
The part load measurements at the reference test conditions shall follow the inlet temperature method of the
Each reference part load test condition is precisely determined by the part load and the inlet temperatures of both indoor and outdoor heat exchangers The inlet temperatures for the indoor heat exchangers are specified in Table 4 and Table 5, while the inlet temperatures for the outdoor heat exchanger are outlined in section 4.3, corresponding to various environmental heat sources.
The average outlet temperatures listed in Tables 4 and 5 serve as a guide for measurements, provided that the nominal heating fluid flow rate remains constant across all part load conditions For low part load ratios (B to F), reducing the heating fluid flow rate can improve outlet temperature accuracy and decrease auxiliary electrical power consumption However, this adjustment is permissible only if the temperature gradient between outlet and inlet temperatures does not exceed the gradient at the corresponding design load condition, which is 7 K for low temperature heat sinks and 10 K, 14 K, and 17 K for medium, high, and very high temperature heat sink applications, respectively.
The recommendations for the hybrid appliance concerning the allowed deviation(s) in the temperature gradients at each reference part load test condition, as described before, shall be followed
Integrated gas-driven sorption heat pumps can operate intermittently or continuously, necessitating a time share with peak boilers at higher heating capacities To determine the heating capacity, it should be averaged over an extended period, such as 24 hours, or across at least two complete operation cycles A typical operation cycle for a hybrid appliance is defined by the interval between two successive normal burner operations.
For burners that maintain a constant air-to-fuel ratio, burner calibration should not be considered a standard operational procedure Testing must occur after two consecutive operational cycles without any automatic calibration intervening The operating manual should detail the cyclic operation of the hybrid appliance, and the automatic burner calibration feature may be disabled during test operations to enhance precision in testing.
Inlet temperatures into the outdoor heat exchanger
Air to water hybrid heating appliance
According to EN 12309-6:2014, the part load ratio (PLR(Toutdoor)) is defined based on the estimated dry bulb air temperatures entering the outdoor heat exchanger of air to water hybrid heating appliances These estimates were derived for the pivot part load test conditions outlined in Table 3, and the results are presented in Table 6.
Table 6 — Inlet dry (wet) bulb temperatures of air into the outdoor heat exchangers
The wet bulb temperature is set equal to the dry bulb temperature minus 1 K For temperature below – 10°C, setting of the wet bulb is not mandatory
For air-to-water hybrid heating systems utilizing exhaust air as a heat source, the reference test conditions should consider an inlet air dry bulb temperature of 20 °C and a wet bulb temperature of 12 °C.
Defrosting of the air heat exchanger must be conducted in accordance with EN 12309-4:2014 if it occurs under any specified test conditions.
The installation of the appliance in the climatic chamber shall follow the installation instructions in accordance with prEN 12309-2:2013 2 and EN 12309-4:2014.
Ground water sourced hybrid heating appliances
For ground water sourced hybrid heating appliances, all 6 reference test part loads (A to F) shall be measured with an inlet temperature of 10 °C into the outdoor heat exchanger.
Ground heat sourced hybrid heating appliances
Following the design conditions presented in Annex B, the listed inlet temperatures to the outdoor heat exchanger in Table 7 at each reference part load test condition shall be applied
Table 7 — Inlet temperatures to the outdoor heat exchanger (evaporator) for the reference part load test conditions
During the measurements, the stated brine flow rates in the operating manual shall be realized.
Solar sourced hybrid heating appliances
According to Annex C, the temperature of brine exiting the solar collectors, which serve as environmental heat sources, surpasses the outdoor dry bulb temperature This temperature difference is related to the collector aperture area, as described by Formula (C.1).
To determine the inlet temperature for the outdoor heat exchanger (evaporator) under reference test conditions A-F, the temperature differences (ΔT) specified in Table 8 must be added to the reference dry-bulb outdoor temperatures provided in Table 6, based on the collector aperture area and type.
2 This part of standard is currently being revised
For air-to-water hybrid heating systems utilizing exhaust air as a heat source, the reference test conditions should consider an inlet air dry bulb temperature of 20 °C and a wet bulb temperature of 12 °C.
In accordance with EN 12309-4:2014, the defrosting process of the air heat exchanger must be evaluated if it occurs under any of the specified test conditions outlined in this subclause.
The installation of the appliance in the climatic chamber shall follow the installation instructions in accordance with prEN 12309-2:2013 2 and EN 12309-4:2014
4.3.2 Ground water sourced hybrid heating appliances
For ground water sourced hybrid heating appliances, all 6 reference test part loads (A to F) shall be measured with an inlet temperature of 10 °C into the outdoor heat exchanger
4.3.3 Ground heat sourced hybrid heating appliances
Following the design conditions presented in Annex B, the listed inlet temperatures to the outdoor heat exchanger in Table 7 at each reference part load test condition shall be applied
Table 7 — Inlet temperatures to the outdoor heat exchanger (evaporator) for the reference part load test conditions
During the measurements, the stated brine flow rates in the operating manual shall be realized
4.3.4 Solar sourced hybrid heating appliances
According to Annex C, the temperature of brine exiting the solar collectors, which utilize environmental heat sources, surpasses the outdoor dry bulb temperature by a difference that is related to the collector aperture area, as described by Formula (C.1).
To determine the inlet temperature for the outdoor heat exchanger (evaporator) under reference test conditions A-F, the temperature differences (ΔT) specified in Table 8 must be added to the reference dry-bulb outdoor temperatures provided in Table 6, based on the collector aperture area and type.
2 This part of standard is currently being revised
Table 8 — Temperature differences between the inlet temperature to the outdoor heat exchanger and the outdoor dry-bulb test conditions given in Table 6
Collector aperture area / maximum heat extraction rate Δ T Δ T
Flat plate Vacuum tube m 2 /kW K K
During the measurements, the stated brine flow rates in the operating manual shall be realized
Solar collectors can serve as an eco-friendly heat source to complement existing ground heat sources or air-brine heat exchangers To estimate the inlet temperature for the outdoor heat exchanger, Annex D can be utilized.
5 Calculation of the seasonal performance in the heating mode
The seasonal performance calculation of hybrid heating appliances utilizes the bin method as outlined in EN 12309-6:2014, sections 5.3 to 5.7 This process involves determining the part load gas utilization efficiency and auxiliary energy factor at each bin temperature through linear interpolation of their respective part load values, which are measured under reference part load test conditions specified in the document for each reference heating season and heat sink design condition.
The seasonal gas utilization efficiency of hybrid heating appliances, which combine sorption heat pumps and solar collectors to partially meet building heating demands, will be evaluated in accordance with Annex E.
Annex F presents a methodology to estimate the seasonal performance of hybrid heating appliances at building heating design loads less than the appliance’s nominal heating capacity
6 Standard rating conditions of gas driven sorption heat pump based hybrid heating appliances
To evaluate gas-driven sorption heat pump-based hybrid heating appliances for marking, comparison, or certification, the following seasonal performance metrics will be utilized: seasonal gas utilization efficiency, seasonal auxiliary energy factor, and seasonal primary energy ratio.
Hybrid heating appliances can be evaluated under the standard rating conditions specified in Table 9 for nominal heating capacity and in Table 10 for the 30% part load condition.
Table 9 — Standard rating test conditions for hybrid heating appliances at nominal heating capacity
Outdoor heat exchanger Indoor heat exchanger Inlet temperature °C
Air sourced low temperature 7 b a 35 medium temperature 7 b a 45 high temperature 7 b a 55 very high temperature 7 b a 65
Ground water sourced low temperature 10 b a 35 medium temperature 10 b a 45 high temperature 10 b a 55 very high temperature 10 b a 65
Ground heat sourced c low temperature 8 b a 35 medium temperature 8 b a 45 high temperature 8 b a 55 very high temperature 8 b a 65
Solar sourced systems operate at various temperature levels: low (12 °C to 35 °C), medium (12 °C to 45 °C), high (12 °C to 55 °C), and very high (12 °C to 65 °C) All tests must be conducted at the nominal flow rates specified in the operating manual, measured in cubic meters per second It is essential that the temperature difference between the outlet and inlet at the indoor heat exchanger does not exceed the maximum temperature difference (ΔT max), which is calculated using the formula: max 7 35 * 10.
The tests will be conducted using the flow rate specified by the appliance's control system, or, if not available, the flow rate measured under standard conditions, ensuring that the maximum temperature difference (ΔT) is maintained The appliance's control system is designed to manage the internal pumps effectively Additionally, the maximum extraction output per probe meter is set at 35 W per meter of probe.
Table 9 — Standard rating test conditions for hybrid heating appliances at nominal heating capacity
Outdoor heat exchanger Indoor heat exchanger Inlet temperature °C
Air sourced low temperature 7 b a 35 medium temperature 7 b a 45 high temperature 7 b a 55 very high temperature 7 b a 65
Ground water sourced low temperature 10 b a 35 medium temperature 10 b a 45 high temperature 10 b a 55 very high temperature 10 b a 65
Ground heat sourced c low temperature 8 b a 35 medium temperature 8 b a 45 high temperature 8 b a 55 very high temperature 8 b a 65
Solar sourced systems operate at various temperature levels: low (12 b a 35), medium (12 b a 45), high (12 b a 55), and very high (12 b a 65) All tests must be conducted at the nominal flow rates specified in the operating manual, measured in cubic meters per second It is essential that the temperature difference between the outlet and inlet at the indoor heat exchanger does not exceed the maximum temperature difference (ΔT max), which can be calculated using the formula: max 7 35 * 10.
The tests will be conducted using the flow rate specified by the appliance's control system or, if not available, the flow rate measured under standard conditions, ensuring that the maximum temperature difference (ΔT) is maintained The appliance's control system is designed to manage the internal pumps effectively Additionally, the maximum extraction output per meter of probe is set at 35 W.
Table 10 — Standard rating test conditions for hybrid heating appliances at 30 % part load condition
Outdoor heat exchanger Indoor heat exchanger Inlet temperature °C
Air sourced low temperature 7 b 22,8 a medium temperature 7 b 25,8 a high temperature 7 b 29,0 a very high temperature 7 b 32,9 a
Ground water sourced low temperature 10 b 22,8 a medium temperature 10 b 25,8 a high temperature 10 b 29,0 a very high temperature 10 b 32,9 a
Ground heat sourced c low temperature 8 b 22,8 a medium temperature 8 b 25,8 a high temperature 8 b 29,0 a very high temperature 8 b 32,9 a
Solar sourced low temperature 12 b 22,8 a medium temperature 12 b 25,8 a high temperature 12 b 29,0 a very high temperature 12 b 32,9 a a The part load measurements at the reference test conditions shall follow the inlet temperature method of
Introduction
When utilizing solar collectors as an alternative environmental heat source alongside an existing ground heat source or an air-brine heat exchanger for air heating, Annex D should be implemented.
Solar-assisted ground sourced gas-driven sorption heat pumps
In the reference part load test conditions, the inlet temperature of the outdoor heat exchanger (evaporator) must be set to the higher value from Table 7 or calculated using Formula (C.1) in conjunction with Table 8 and Table 6 This method is applicable only when alternating between GHS and solar collectors, depending on which source provides the highest temperature.
Solar-assisted air sourced gas-driven sorption heat pumps
The inlet temperature of the outdoor heat exchanger (evaporator) should be determined based on the higher value from Table 6 or the results obtained from Formula (C.1) or Table 8, in conjunction with Table 6 of this document, under the reference part load test conditions This method is applicable only when alternating between air heat sources or solar collectors, depending on which source provides the highest temperature.
Inlet temperature of the outdoor heat exchanger for solar collector assisted sorption heat pump based hybrid heating appliances
When utilizing solar collectors as an alternative environmental heat source alongside an existing ground heat source or an air-brine heat exchanger for air heating, Annex D should be implemented.
D.2 Solar-assisted ground sourced gas-driven sorption heat pumps
During the measurements of the reference part load test conditions, the respective outdoor heat exchanger’s
(evaporator) inlet temperature is to be set to the higher value out of Table 7 and those obtained from
The methodology outlined in Formula (C.1) and Table 8, in conjunction with Table 6, is applicable for the alternative utilization of either GHS or solar collectors, based on the source that provides the highest temperature.
D.3 Solar-assisted air sourced gas-driven sorption heat pumps
The inlet temperature of the outdoor heat exchanger (evaporator) should be determined based on the reference part load test conditions, using the higher value from Table 6 or the results from Formula (C.1) and Table 8 This method is applicable when alternating between air heat sources or solar collectors, depending on which source provides the highest temperature.
Calculation of the seasonal gas utilization efficiency with partial heat demand coverage by the applied solar collectors
The seasonal gas utilization efficiency for hybrid heating appliances that utilize sorption heat pumps, which partially meet building heating demands through solar collectors acting as an environmental heat source, is determined using Formula (E.1).
SGUEh S is the Seasonal Gas Utilization Efficiency for heating with solar contribution
SGUEh is the estimated seasonal gas utilization efficiency as defined by prEN 12309–6:2012, 5.4,
Formula (9), according to the test conditions defined by this document for solar sourced hybrid heating appliances;
X is the fraction of the seasonal heating demand of the building covered by the solar collectors
Estimation of the seasonal performance of hybrid heating appliances at building design loads deviating from the appliance's nominal heating capacity
The nominal heating capacity represents the maximum output of a hybrid heating appliance If the heating load required by the building design is less than this nominal capacity, it is necessary to repeat the entire measurement campaign for each specific heating load of the building design.
To minimize experimental effort, it is recommended to establish two nominal heating capacities for each hybrid heating appliance: the highest and lowest nominal heating capacities.
The condition for applying a specific hybrid heating appliance is that the building design load for heating shall lie between the lowest and highest nominal capacities of the considered appliance
The measuring campaign will focus solely on the two nominal heating capacities The reference part load gas utilization efficiency and auxiliary energy factor will be linearly interpolated between the values at the highest and lowest nominal capacities for any building design load for heating that falls within this range.
Estimation of the seasonal performance of hybrid heating appliances at building design loads deviating from the appliance's nominal heating capacity
The nominal heating capacity represents the maximum output of a hybrid heating appliance If the heating load required by the building design is less than this nominal capacity, it is necessary to repeat the entire measurement campaign for each specific heating load of the building design.
To minimize experimental effort, it is recommended to establish two nominal heating capacities for each hybrid heating appliance: the highest and lowest nominal heating capacities.
The condition for applying a specific hybrid heating appliance is that the building design load for heating shall lie between the lowest and highest nominal capacities of the considered appliance
The measuring campaign will focus solely on the two nominal heating capacities The reference part load gas utilization efficiency and auxiliary energy factor will be linearly interpolated between the values at the highest and lowest nominal capacities for any building design load for heating that falls within this range.
Calculation of the seasonal space heating energy efficiency for hybrid gas-driven sorption heat pump based heating appliances
The seasonal space heating energy efficiency η s is defined for hybrid gas-driven sorption heat pump based heating appliances as:
SPER reference Seasonal Primary Energy Ratio
F(i): are corrections calculated according to the following paragraphs and are expressed in %
The correction factor F(1) addresses the negative impact on the seasonal space heating energy efficiency of heaters, considering the adjusted contributions of temperature controls in various heating systems, including those with solar-only systems and passive flue heat recovery devices For hybrid gas-driven sorption heat pump-based heating appliances and combination heaters, F(1) is set at 3% Additionally, the correction factor F(2) reflects the negative contribution to seasonal space heating energy efficiency due to the electricity consumption of pumps that circulate the heat transfer fluid between the hybrid heating appliance and the ambient heat source, which can be ground, water, or solar Table G.1 provides the specific values of F(2) for each type of ambient heat source used in hybrid appliances.
Table G.1 — F(2) values for each ambient heat source of the hybrid appliances
Ground Water – Water Heat Pumps 2
Ground/Brine – Water Heat Pumps 1
The correction factor F(3) enhances the seasonal space heating energy efficiency of hybrid gas-driven sorption heat pump systems by accounting for the positive impact of various temperature control classes The specific values for F(3) are determined based on the control class, as outlined in Table G.2.
Table G.2 — F(3) values assigned according to the control class
Class Definition of temperature control [-F(3)]
The I On/Off Room Thermostat regulates the operation of a heater by controlling its on/off function The performance of this thermostat, including its switching differential and accuracy in room temperature control, is influenced by its mechanical design.
The weather compensator control for modulating heaters adjusts the flow temperature set point based on the current outside temperature and a chosen weather compensation curve This system effectively modulates the heater's output to optimize performance and energy efficiency.