Periodic Reporting for period 2 - PRHYDE (Protocol for heavy duty hydrogen refuelling)
Okres sprawozdawczy: 2021-04-01 do 2022-09-30
The lack of standardized in heavy duty vehicles (HD) fuelling protocols is seen as one of the major challenges preventing ramp-up of hydrogen refuelling stations (HRS) and fuel cell trucks.
Consequently, a new international standard has to be developed for efficient & safe hydrogen refuelling as existing ones are not sufficient for heavy duty vehicles. Current hydrogen refuelling protocols are developed for LDV & are not optimized for high-performance refuelling of HDV, especially with high pressure hydrogen tanks (70 MPa):
- The existing hydrogen refuelling concepts are based on most conservative, worst-case assumptions for safe refuelling and are not suited / scalable for HDV refuelling (with increased H2 flow rate requirements).
- Today, only the station is “responsible” for hydrogen refuelling and no real vehicle characteristics / data are used (i.e. no communication on performance and tank data between HRS and H2 vehicle).
- Existing US (SAE J2601) or Japanese protocols (JPEC s-003) (under review) are not applicable to be referenced in EU regulatory (EU New Legislative Framework).
In January 2022, the International Organization for Standardization (ISO TC 197 WG 24, TF 3) has started its work for the development of this specific standard for highly efficient and safe hydrogen refuelling for HDV.
The overall objective of this PRHYDE project was to support the standardization organisations and to accelerate this protocol development for high performance H2 refuelling of HDV (35/50/70 MPa). Between January 2020 and September 2022, the PRHYDE partners and further external experts have developed specific H2 refuelling concepts, technical specifications and methodologies that are provided as inputs & support to the standardization groups (i.e. for ISO and SAE).
Funded by the Fuel Cells and Hydrogen 2 Joint Undertaking (now Clean Hydrogen Partnership) and supported by international companies and institutes in Europe, USA, and Asia, the PRHYDE project has developed several fuelling concepts for HDV refuelling and formulated recommendations for further work to standardisation organisations, politics and hardware developers.
Consequently, a new international standard has to be developed for efficient & safe hydrogen refuelling as existing ones are not sufficient for heavy duty vehicles. Current hydrogen refuelling protocols are developed for LDV & are not optimized for high-performance refuelling of HDV, especially with high pressure hydrogen tanks (70 MPa):
- The existing hydrogen refuelling concepts are based on most conservative, worst-case assumptions for safe refuelling and are not suited / scalable for HDV refuelling (with increased H2 flow rate requirements).
- Today, only the station is “responsible” for hydrogen refuelling and no real vehicle characteristics / data are used (i.e. no communication on performance and tank data between HRS and H2 vehicle).
- Existing US (SAE J2601) or Japanese protocols (JPEC s-003) (under review) are not applicable to be referenced in EU regulatory (EU New Legislative Framework).
In January 2022, the International Organization for Standardization (ISO TC 197 WG 24, TF 3) has started its work for the development of this specific standard for highly efficient and safe hydrogen refuelling for HDV.
The overall objective of this PRHYDE project was to support the standardization organisations and to accelerate this protocol development for high performance H2 refuelling of HDV (35/50/70 MPa). Between January 2020 and September 2022, the PRHYDE partners and further external experts have developed specific H2 refuelling concepts, technical specifications and methodologies that are provided as inputs & support to the standardization groups (i.e. for ISO and SAE).
Funded by the Fuel Cells and Hydrogen 2 Joint Undertaking (now Clean Hydrogen Partnership) and supported by international companies and institutes in Europe, USA, and Asia, the PRHYDE project has developed several fuelling concepts for HDV refuelling and formulated recommendations for further work to standardisation organisations, politics and hardware developers.
The PRHYDE project started in January 2020 with a state-of-the-art analysis and the definition of specifications for heavy duty vehicle (HVD) fuelling (work package 2, WP2). This includes relevant requirements including aspects such as vehicle driving range, fuelling time, tank sizes, average kg/fill and, State of Charge (SoC) and commercial boundary conditions of typical HDV operators. In addition, an assessment of existing refuelling risk assessment analyses with focus on new concept approaches was performed as well as a gap analysis of existing hardware used in heavy duty gaseous hydrogen refuelling. Based also on a further gap analysis of existing gaseous refuelling protocols, targets for a future refuelling protocol were defined.
In WP3, concepts for hydrogen refuelling protocols of heavy-duty vehicles were discussed and developed. WP3 has provided and defined specifications for the modelling and experimental validation tests. In addition, a preliminary/partial safety and risk assessment of threats of the new refuelling protocols was performed- Based on the test results from modelling and fuelling tests, first draft protocol concepts were further optimized throughout the project.
In WP4, simulations for selected H2 tanks were performed. After preliminary calculations and the definition of measurement conditions during the first report period, specific CFD cases for the tanks and the injection system were tested and documented.
WP5 was responsible for the planning, preparation and performing several refuelling tests based on specifications of WP3. Accordingly, different hydrogen single tanks (35, 50 and70 MPa) were selected/purchased, equipped with thermocouples and tested at different test sites.
For stakeholder and expert discussions, six webinars/workshops and a survey have been organized in the context of WP6 (Recommendations and Dissemination). The results of the online webinars, surveys and final documents (results & recommendations) have been published as deliverables on the PRHYDE website. Furthermore several meetings with standardization organization (e.g. SAE FCEV Interface Task Force (ITF), ISO/TC 197/WG 24 or CEN TC 256 WG43) and exchange with other expert groups (i.e. CEP, CARA) were organized during the project duration.
In WP3, concepts for hydrogen refuelling protocols of heavy-duty vehicles were discussed and developed. WP3 has provided and defined specifications for the modelling and experimental validation tests. In addition, a preliminary/partial safety and risk assessment of threats of the new refuelling protocols was performed- Based on the test results from modelling and fuelling tests, first draft protocol concepts were further optimized throughout the project.
In WP4, simulations for selected H2 tanks were performed. After preliminary calculations and the definition of measurement conditions during the first report period, specific CFD cases for the tanks and the injection system were tested and documented.
WP5 was responsible for the planning, preparation and performing several refuelling tests based on specifications of WP3. Accordingly, different hydrogen single tanks (35, 50 and70 MPa) were selected/purchased, equipped with thermocouples and tested at different test sites.
For stakeholder and expert discussions, six webinars/workshops and a survey have been organized in the context of WP6 (Recommendations and Dissemination). The results of the online webinars, surveys and final documents (results & recommendations) have been published as deliverables on the PRHYDE website. Furthermore several meetings with standardization organization (e.g. SAE FCEV Interface Task Force (ITF), ISO/TC 197/WG 24 or CEN TC 256 WG43) and exchange with other expert groups (i.e. CEP, CARA) were organized during the project duration.
The PRHYDE protocol concepts are based on the MC Formula Framework known from SAE J2601 standard, allowing a number of previously defined parameters to be reused and referenced. A paradigm shift in use of communicated data prepares the PRHYDE protocol concepts to be adaptable to future component and technology advances in the hydrogen automotive industry. Key element of the PRHYDE hydrogen refuelling concepts considers advanced communication between HRS and vehicle which results in an increasingly relying on the data communicated from vehicle to station.
A map of Protocol Types was developed based on Protocol Levels (of communication usage), Protocol Approach (to fueling parameters) and Protocol Fill Control. Out of the various Protocol Types available, four concepts were defined, using following nomenclature (with PR = Prescriptive; PB = Performance Based; S = Station Control, CHSS = Compressed Hydrogen Storage System):
- Type 2-PR-S Static Data (CHSS gas temperature is not taken into account. CHSS temperature is assumed to be at hot-soak conditions.)
- Type 3-PR-S Dynamic Data – T_gas Initial (CHSS gas temperature is used to screen for fueling history, which if absent allows higher P_min values to be used based on P_initial.)
- Type 3-PR-S Dynamic Data – T_gas Initial+ (CHSS gas temperature is taken into account. CHSS gas temperature is used to choose a set of t-final tables with different CHSS soak temperatures in combination with different P_min values based on P_initial.)
- Type 3-PR-S Dynamic Data – T_gas Throttle (CHSS gas temperature is taken into account. The actual CHSS gas temperature (T_gas_high) is used to reduce the pressure ramp rate (PRR) when a threshold temperature is reached. The t-final table is derived with a higher CHSS gas temperature (e.g. 95 degree C) facilitating faster fueling in the early portion of the fill.)
To adjust the fueling speed when station meets non-ideal situations such as low storage capacity or high flow restrictions, the so-called SOC Taper was also developed.
Simulation validation (thermodynamic modelling and Computational Fluid Dynamics) and field tests were conducted at different test facilities during two specific test phases (between May 21 and August 22). The analysis led to optimizations of the PRHYDE concepts; especially for the T_gas Throttle concept.
Ultimately performance estimates of the developed PRHYDE protocol concepts were conducted based on simulations and referenced for implications on how these fueling concepts can improve fueling time in the heavy duty segment. The simulations indicated the concepts to have significant reductions in fueling time due to the elimination of many of the inherent embedded worst-case assumptions. Fueling times less than 10 minutes can be realized under all fueling conditions and with the Type 3 PRHYDE fueling concepts (T_gas Initial, T_gas Initial+ and T_gas Throttle). Furthermore, fueling times less than five minutes can be realized under many typical fueling conditions.
A map of Protocol Types was developed based on Protocol Levels (of communication usage), Protocol Approach (to fueling parameters) and Protocol Fill Control. Out of the various Protocol Types available, four concepts were defined, using following nomenclature (with PR = Prescriptive; PB = Performance Based; S = Station Control, CHSS = Compressed Hydrogen Storage System):
- Type 2-PR-S Static Data (CHSS gas temperature is not taken into account. CHSS temperature is assumed to be at hot-soak conditions.)
- Type 3-PR-S Dynamic Data – T_gas Initial (CHSS gas temperature is used to screen for fueling history, which if absent allows higher P_min values to be used based on P_initial.)
- Type 3-PR-S Dynamic Data – T_gas Initial+ (CHSS gas temperature is taken into account. CHSS gas temperature is used to choose a set of t-final tables with different CHSS soak temperatures in combination with different P_min values based on P_initial.)
- Type 3-PR-S Dynamic Data – T_gas Throttle (CHSS gas temperature is taken into account. The actual CHSS gas temperature (T_gas_high) is used to reduce the pressure ramp rate (PRR) when a threshold temperature is reached. The t-final table is derived with a higher CHSS gas temperature (e.g. 95 degree C) facilitating faster fueling in the early portion of the fill.)
To adjust the fueling speed when station meets non-ideal situations such as low storage capacity or high flow restrictions, the so-called SOC Taper was also developed.
Simulation validation (thermodynamic modelling and Computational Fluid Dynamics) and field tests were conducted at different test facilities during two specific test phases (between May 21 and August 22). The analysis led to optimizations of the PRHYDE concepts; especially for the T_gas Throttle concept.
Ultimately performance estimates of the developed PRHYDE protocol concepts were conducted based on simulations and referenced for implications on how these fueling concepts can improve fueling time in the heavy duty segment. The simulations indicated the concepts to have significant reductions in fueling time due to the elimination of many of the inherent embedded worst-case assumptions. Fueling times less than 10 minutes can be realized under all fueling conditions and with the Type 3 PRHYDE fueling concepts (T_gas Initial, T_gas Initial+ and T_gas Throttle). Furthermore, fueling times less than five minutes can be realized under many typical fueling conditions.