Solar water heaters

1. Scope and Applicability

This rule covers an accepted complete solar water heater as sold, including its collector, storage tank, and connection components supplied in the declared configuration. Flat-plate and evacuated-tube routes are in scope and must be declared. The foreground starts when purchased stock, glazing, insulation, and components enter the factory and ends with the packaged finished heater at the factory gate. Upstream material and energy production connect through background datasets. Installation, operation, maintenance, and end of life are outside this manufacturing dataset. Standalone collectors, tanks, parts, photovoltaics, and electric-only water heaters are excluded. The manufacturing decomposition follows chapter 8, Tables 70 and 71 of greening-2013; its UK operation scenario and case values are not generic manufacturing values.

2. Product Category Identity

Field	Value
canonical_pcr_id	pcr.metal-products-machinery-and-equipment.special-purpose-machinery.solar-water-heaters
classification_refs	CPC 3.0 44826: Solar water heaters; un-cpc-3-2025
covered_products	Complete factory-made solar water heaters with collector and storage tank, flat-plate or evacuated-tube
excluded_products	Standalone collectors, standalone tanks, components, photovoltaics, electric-only heaters, site-built custom installations
representative_product	One accepted complete solar water heater of declared configuration
production_route	Collector fabrication; storage tank fabrication; final assembly and packaging
market_state	Packaged at factory gate; packaging mass excluded from net product mass M

3. Reference Flow

Field	Value
What	A complete device for heating domestic water using solar thermal energy
How much	One accepted finished machine of declared configuration with net mass M kg
How well	Record collector type, tank volume, rated performance and supplied parts; no universal performance value
How long or cycle	One unit at factory delivery; service life is outside this manufacturing dataset
reference_flow_link	a_finished

Field	Value
Reference amount	M
Reference product flow	Solar water heaters 9ede182c-cfec-4513-a405-b17db74ed710
Reference flow property	Mass 93a60a56-a3c8-11da-a746-0800200b9a66
Reference unit group	Units of mass 93a60a57-a4c8-11da-a746-0800200c9a66
Reference unit	kg
Required qualifiers	model; same configuration; collector technology; tank volume; supplied pump and heat-transfer fluid; packaging; accepted net mass M; factory location and period

A foreground data package must declare the required qualifiers in metadata or equivalent process records.

4. Measurement and Unit Rules

rule_id	Applies to	Required property	Required unit	Rule
reference_mass	reference product	Mass	kg	M = accepted net mass of one complete machine of the same configuration in kg; collect using cp_mass.

5. System Boundary

Boundary Abstraction

Field	Value
declared_starting_condition	Quantity and state of purchased materials and components entering the manufacturing facility
starting_condition_role	Foreground entry; upstream production covered by traceable background datasets
product_classification_scope	Complete CPC 44826 solar water heaters; any purchased complete heater is separately identified
recursive_input_rule	Do not recursively use this rule to model a purchased complete heater used as an input; link it as a distinct upstream dataset and disclose its quantity
upstream_dataset_requirement	Link upstream material, energy, and purchased-component datasets compatible with geography, technology, and time
disclosure	Declare configuration, supply state, purchased components, plant processes, packaging boundary, and exclusions

rule_id	applies_to	rule	source_ids
boundary_1	manufacturing boundary	Include collector, tank, assembly, and supplied packaging; record actual inputs and wastes for the applicable configuration.	greening-2013
boundary_2	life-cycle stages	Model installation, operation, maintenance, and end of life separately; this manufacturing dataset ends at the factory gate.	greening-2013

6. Process Inventory Structure

Process Map

process_id	process_name	inclusion	inclusion_condition	role	quantitative_reference
collector	Collector fabrication	required	none	foreground manufacturing	per one accepted finished machine
tank	Storage tank fabrication	required	none	foreground manufacturing	per one accepted finished machine
assembly	Final assembly and packaging	required	none	foreground manufacturing	per one accepted finished machine

Process: Collector fabrication (collector)

Inputs

Product flows

Frame steel sheet (c_steel_sheet)

Include when all collector routes; use records for the same accepted configuration.

• Selected flow: Low-alloy steel sheet
• Flow property / unit: Mass / kg
• Amount rule: Record and allocate to accepted finished machines using cp_collector_bom.
• Value mode: Foreground record (foreground_record)
• Specificity: Site-specific (site_specific)
• Normalization basis: per one accepted finished machine
• Basis kind: Reference flow (reference_flow)
• Evidence kind: Collected record (collected_record)
• Collection protocol: cp_collector_bom
• Sources: greening-2013

Flat-plate absorber copper sheet (c_copper_sheet)

Include when flat-plate collector only; use records for the same accepted configuration.

• Selected flow: Copper sheet 30cc5ca3-6198-4f82-8016-284f1b15d01b
• Flow property / unit: Mass / kg
• Amount rule: Record and allocate to accepted finished machines using cp_collector_bom.
• Value mode: Foreground record (foreground_record)
• Specificity: Site-specific (site_specific)
• Normalization basis: per one accepted finished machine
• Basis kind: Reference flow (reference_flow)
• Evidence kind: Collected record (collected_record)
• Collection protocol: cp_collector_bom
• Sources: greening-2013

Flat-plate glazing (c_flat_glass)

Include when flat-plate collector only; use records for the same accepted configuration.

• Selected flow: Low-iron flat glass
• Flow property / unit: Mass / kg
• Amount rule: Record and allocate to accepted finished machines using cp_collector_bom.
• Value mode: Foreground record (foreground_record)
• Specificity: Site-specific (site_specific)
• Normalization basis: per one accepted finished machine
• Basis kind: Reference flow (reference_flow)
• Evidence kind: Collected record (collected_record)
• Collection protocol: cp_collector_bom
• Sources: greening-2013

Evacuated glass tube (c_glass_tube)

Include when evacuated-tube collector only; use records for the same accepted configuration.

• Selected flow: Borosilicate glass tube
• Flow property / unit: Mass / kg
• Amount rule: Record and allocate to accepted finished machines using cp_collector_bom.
• Value mode: Foreground record (foreground_record)
• Specificity: Site-specific (site_specific)
• Normalization basis: per one accepted finished machine
• Basis kind: Reference flow (reference_flow)
• Evidence kind: Collected record (collected_record)
• Collection protocol: cp_collector_bom
• Sources: greening-2013

Collector frame aluminium sheet (c_aluminium_sheet)

Include when when aluminium framing is installed; use records for the same accepted configuration.

• Selected flow: aluminium sheet 4f197be4-7b3b-11dd-ad8b-0800200c9a66
• Flow property / unit: Mass / kg
• Amount rule: Record and allocate to accepted finished machines using cp_collector_bom.
• Value mode: Foreground record (foreground_record)
• Specificity: Site-specific (site_specific)
• Normalization basis: per one accepted finished machine
• Basis kind: Reference flow (reference_flow)
• Evidence kind: Collected record (collected_record)
• Collection protocol: cp_collector_bom
• Sources: greening-2013

Collector manufacturing electricity (c_electricity)

Include when all collector routes; use records for the same accepted configuration.

• Selected flow: Alternating current a500e350-83b8-4347-894e-b81ecd418615
• Flow property / unit: Net calorific value / MJ
• Amount rule: Record and allocate to accepted finished machines using cp_collector_energy.
• Value mode: Foreground record (foreground_record)
• Specificity: Site-specific (site_specific)
• Normalization basis: per one accepted finished machine
• Basis kind: Reference flow (reference_flow)
• Evidence kind: Collected record (collected_record)
• Collection protocol: cp_collector_energy
• Sources: greening-2013

Waste flows

Elementary flows

Outputs

Product flows

Waste flows

Collector steel offcuts (c_steel_scrap)

Include when when steel cutting creates offcuts; use records for the same accepted configuration.

• Selected flow: Steel scrap 37997e0e-e34b-4ab9-a642-5d86f4333919
• Flow property / unit: Mass / kg
• Amount rule: Record and allocate to accepted finished machines using cp_collector_scrap.
• Value mode: Foreground record (foreground_record)
• Specificity: Site-specific (site_specific)
• Normalization basis: per one accepted finished machine
• Basis kind: Reference flow (reference_flow)
• Evidence kind: Collected record (collected_record)
• Collection protocol: cp_collector_scrap
• Sources:

Elementary flows

Process: Storage tank fabrication (tank)

Inputs

Product flows

Tank steel sheet (t_steel_sheet)

Include when all tank routes; use records for the same accepted configuration.

• Selected flow: Low-alloy steel sheet
• Flow property / unit: Mass / kg
• Amount rule: Record and allocate to accepted finished machines using cp_tank_bom.
• Value mode: Foreground record (foreground_record)
• Specificity: Site-specific (site_specific)
• Normalization basis: per one accepted finished machine
• Basis kind: Reference flow (reference_flow)
• Evidence kind: Collected record (collected_record)
• Collection protocol: cp_tank_bom
• Sources: greening-2013

Tank insulation glass wool (t_glass_wool)

Include when when glass-wool insulation is fitted; use records for the same accepted configuration.

• Selected flow: Glass Wool 85977f80-d866-44ec-bac9-52cb2d9fb421
• Flow property / unit: Mass / kg
• Amount rule: Record and allocate to accepted finished machines using cp_tank_bom.
• Value mode: Foreground record (foreground_record)
• Specificity: Site-specific (site_specific)
• Normalization basis: per one accepted finished machine
• Basis kind: Reference flow (reference_flow)
• Evidence kind: Collected record (collected_record)
• Collection protocol: cp_tank_bom
• Sources: greening-2013

Tank manufacturing electricity (t_electricity)

Include when all tank routes; use records for the same accepted configuration.

• Selected flow: Alternating current a500e350-83b8-4347-894e-b81ecd418615
• Flow property / unit: Net calorific value / MJ
• Amount rule: Record and allocate to accepted finished machines using cp_tank_energy.
• Value mode: Foreground record (foreground_record)
• Specificity: Site-specific (site_specific)
• Normalization basis: per one accepted finished machine
• Basis kind: Reference flow (reference_flow)
• Evidence kind: Collected record (collected_record)
• Collection protocol: cp_tank_energy
• Sources: greening-2013

Tank heating natural gas (t_natural_gas)

Include when when pipeline-quality natural gas fires a manufacturing step; use records for the same accepted configuration.

• Selected flow: Pipeline-quality natural gas 7766e51e-0b64-4fbb-89cb-489c33293137
• Flow property / unit: Volume / m3
• Amount rule: Record and allocate to accepted finished machines using cp_tank_fuel.
• Value mode: Foreground record (foreground_record)
• Specificity: Site-specific (site_specific)
• Normalization basis: per one accepted finished machine
• Basis kind: Reference flow (reference_flow)
• Evidence kind: Collected record (collected_record)
• Collection protocol: cp_tank_fuel
• Sources: greening-2013

Tank test water (t_tap_water)

Include when when hydrostatic testing uses tap water; use records for the same accepted configuration.

• Selected flow: Tap water d1e0e36c-07f0-4a75-bdcb-efb5d9e2ac36
• Flow property / unit: Mass / kg
• Amount rule: Record and allocate to accepted finished machines using cp_tank_test_water.
• Value mode: Foreground record (foreground_record)
• Specificity: Site-specific (site_specific)
• Normalization basis: per one accepted finished machine
• Basis kind: Reference flow (reference_flow)
• Evidence kind: Collected record (collected_record)
• Collection protocol: cp_tank_test_water
• Sources: greening-2013

Waste flows

Elementary flows

Outputs

Product flows

Waste flows

Tank steel offcuts (t_steel_scrap)

Include when when steel cutting creates offcuts; use records for the same accepted configuration.

• Selected flow: Steel scrap 37997e0e-e34b-4ab9-a642-5d86f4333919
• Flow property / unit: Mass / kg
• Amount rule: Record and allocate to accepted finished machines using cp_tank_scrap.
• Value mode: Foreground record (foreground_record)
• Specificity: Site-specific (site_specific)
• Normalization basis: per one accepted finished machine
• Basis kind: Reference flow (reference_flow)
• Evidence kind: Collected record (collected_record)
• Collection protocol: cp_tank_scrap
• Sources:

Discharged tank test water (t_test_water_waste)

Include when when test water leaves the process; use records for the same accepted configuration.

• Selected flow: Used hydrostatic-test water
• Flow property / unit: Mass / kg
• Amount rule: Record and allocate to accepted finished machines using cp_tank_test_water.
• Value mode: Foreground record (foreground_record)
• Specificity: Site-specific (site_specific)
• Normalization basis: per one accepted finished machine
• Basis kind: Reference flow (reference_flow)
• Evidence kind: Collected record (collected_record)
• Collection protocol: cp_tank_test_water
• Sources:

Elementary flows

Process: Final assembly and packaging (assembly)

Inputs

Product flows

Connection copper pipe (a_copper_pipe)

Include when when copper pipe is supplied with the finished heater; use records for the same accepted configuration.

• Selected flow: Copper tubing 0d80f4b8-8f26-4eee-8b81-df499c4c9dff
• Flow property / unit: Mass / kg
• Amount rule: Record and allocate to accepted finished machines using cp_assembly_bom.
• Value mode: Foreground record (foreground_record)
• Specificity: Site-specific (site_specific)
• Normalization basis: per one accepted finished machine
• Basis kind: Reference flow (reference_flow)
• Evidence kind: Collected record (collected_record)
• Collection protocol: cp_assembly_bom
• Sources: greening-2013

Integral circulation pump (a_pump)

Include when active circulating package only; use records for the same accepted configuration.

• Selected flow: Circulation pump
• Flow property / unit: Mass / kg
• Amount rule: Record and allocate to accepted finished machines using cp_assembly_bom.
• Value mode: Foreground record (foreground_record)
• Specificity: Site-specific (site_specific)
• Normalization basis: per one accepted finished machine
• Basis kind: Reference flow (reference_flow)
• Evidence kind: Collected record (collected_record)
• Collection protocol: cp_assembly_bom
• Sources: greening-2013

Factory-charged propylene glycol (a_glycol)

Include when when heat-transfer circuit is charged at the factory; use records for the same accepted configuration.

• Selected flow: Propylene glycol
• Flow property / unit: Mass / kg
• Amount rule: Record and allocate to accepted finished machines using cp_assembly_bom.
• Value mode: Foreground record (foreground_record)
• Specificity: Site-specific (site_specific)
• Normalization basis: per one accepted finished machine
• Basis kind: Reference flow (reference_flow)
• Evidence kind: Collected record (collected_record)
• Collection protocol: cp_assembly_bom
• Sources: greening-2013

Corrugated board packaging (a_cardboard)

Include when when corrugated board is supplied as transport packaging; use records for the same accepted configuration.

• Selected flow: Corrugated cardboard 8bde297e-98df-463f-bcb4-0db52bf6e0b5
• Flow property / unit: Mass / kg
• Amount rule: Record and allocate to accepted finished machines using cp_assembly_bom.
• Value mode: Foreground record (foreground_record)
• Specificity: Site-specific (site_specific)
• Normalization basis: per one accepted finished machine
• Basis kind: Reference flow (reference_flow)
• Evidence kind: Collected record (collected_record)
• Collection protocol: cp_assembly_bom
• Sources: greening-2013

Final assembly electricity (a_electricity)

Include when all assembly routes; use records for the same accepted configuration.

• Selected flow: Alternating current a500e350-83b8-4347-894e-b81ecd418615
• Flow property / unit: Net calorific value / MJ
• Amount rule: Record and allocate to accepted finished machines using cp_assembly_energy.
• Value mode: Foreground record (foreground_record)
• Specificity: Site-specific (site_specific)
• Normalization basis: per one accepted finished machine
• Basis kind: Reference flow (reference_flow)
• Evidence kind: Collected record (collected_record)
• Collection protocol: cp_assembly_energy
• Sources: greening-2013

Waste flows

Elementary flows

Outputs

Product flows

Finished solar water heater (a_finished)

Include when all accepted units; use records for the same accepted configuration.

• Selected flow: Solar water heaters 9ede182c-cfec-4513-a405-b17db74ed710
• Flow property / unit: Mass / kg
• Amount rule: M kg
• Value mode: Foreground record (foreground_record)
• Specificity: Site-specific (site_specific)
• Normalization basis: per one accepted finished machine
• Basis kind: Reference flow (reference_flow)
• Evidence kind: Collected record (collected_record)
• Collection protocol: cp_mass
• Sources: greening-2013

Waste flows

Elementary flows

7. Allocation and Co-product Handling

rule_id	applies_to	rule	source_ids
allocation_1	shared manufacturing resources	Prefer separately metered process and batch records; allocate shared meters by documented machine operating time or accepted production count and disclose the method.
allocation_2	steel offcuts	Report offcuts as distinct waste outputs; credit recycling only with separate evidence and consistent downstream boundary to avoid double counting.

8. Foreground Data Collection, Calculation, and Quality Rules

Data Collection Protocols

protocol_id	process_id	flow_role	record_type	raw_fields	collection_method	unit	frequency	temporal_coverage	site_scope	aggregation_rule	quality_evidence
cp_mass	assembly	finished heater	weighing record	model; configuration; serial number; accepted net mass M	Weigh the accepted complete machine on a calibrated scale, excluding transport packaging; reconcile the same configuration and acceptance record.	kg	each accepted unit	representative production year	one declared factory	accepted net mass per machine	calibration certificate and acceptance record
cp_collector_bom	collector	stock materials	batch BOM	model; configuration; material code; issued mass; returned mass; accepted unit count	Reconcile stores issues and returns to accepted collector units.	kg	each production batch	representative production year	collector line	per one accepted finished machine	BOM and stores ledger
cp_tank_bom	tank	stock materials	batch BOM	model; configuration; material code; issued mass; returned mass; accepted unit count	Reconcile stores issues and returns to accepted tank units.	kg	each production batch	representative production year	tank line	per one accepted finished machine	BOM and stores ledger
cp_assembly_bom	assembly	supplied components	batch BOM	model; configuration; component code; issued mass; returned mass; accepted unit count	Reconcile purchased components and packaging to accepted finished heaters.	kg	each production batch	representative production year	assembly line	per one accepted finished machine	BOM and stores ledger
cp_collector_energy	collector	electricity	meter log	meter opening; meter closing; accepted unit count	Read allocated collector-line electricity meter and convert to MJ.	MJ	each production batch	representative production year	collector line	per one accepted finished machine	meter log and allocation record
cp_tank_energy	tank	electricity	meter log	meter opening; meter closing; accepted unit count	Read allocated tank-line electricity meter and convert to MJ.	MJ	each production batch	representative production year	tank line	per one accepted finished machine	meter log and allocation record
cp_assembly_energy	assembly	electricity	meter log	meter opening; meter closing; accepted unit count	Read allocated assembly-line electricity meter and convert to MJ.	MJ	each production batch	representative production year	assembly line	per one accepted finished machine	meter log and allocation record
cp_tank_fuel	tank	natural gas	fuel meter log	fuel meter opening; fuel meter closing; accepted unit count	Measure pipeline-quality natural gas volume from a calibrated meter.	m3	each production batch	representative production year	tank line	per one accepted finished machine	fuel invoice and calorific-value record
cp_collector_scrap	collector	steel offcuts	weighed waste ledger	waste code; net offcut mass; accepted unit count	Weigh segregated collector steel offcuts.	kg	each production batch	representative production year	collector line	per one accepted finished machine	scale ticket and waste transfer note
cp_tank_scrap	tank	steel offcuts	weighed waste ledger	waste code; net offcut mass; accepted unit count	Weigh segregated tank steel offcuts.	kg	each production batch	representative production year	tank line	per one accepted finished machine	scale ticket and waste transfer note
cp_tank_test_water	tank	test water	water meter and discharge log	water meter; discharge meter; accepted unit count	Measure supplied and discharged hydrostatic-test water separately.	kg	each production batch	representative production year	tank line	per one accepted finished machine	water meter and discharge log

Calculation Rules

rule_id	Applies to	Formula or rule	Inputs	Output	source_ids
batch_average	shared batch records	Amount per machine = net batch quantity / accepted finished machines of the same configuration; exclude rework and rejects.	net batch quantity; accepted finished machine count	amount per machine

Data Quality Requirements

requirement_id	Applies to	Requirement	Evidence
dq_1	all inventory rows	Keep the same configuration, production period, and measured units; reconcile batch acceptance counts.	batch ledger; calibration record
dq_2	conditional rows	Disclose route applicability and missing data; do not silently code an unobserved route as zero.	configuration list; process record

9. Validation Rules

rule_id	applies_to	rule	source_ids
validation_1	reference flow	Check a_finished is M kg; M comes from cp_mass for the same configuration and excludes transport packaging.
validation_2	materials and energy	Check batch coverage for inputs, offcuts, test water, and accepted output; disclose unreconciled mass differences.
validation_3	routes and scope	Check applicability of flat-plate and evacuated-tube rows and of pump, heat-transfer fluid, gas, and test water.	greening-2013

10. Published Dataset Profile

Field	Value
dataset_role	Solar water heater factory-gate foreground data package
downstream_use	May serve as secondary_dataset or background_dataset linked to installation, use, and end-of-life models
allowed_use	Manufacturing-stage modelling for matching configuration, geography, time, and product state
excluded_use	Do not use this factory-gate dataset as a full-life-cycle hot-water service or default performance for other technologies
required_metadata	model; collector route; tank volume; supplied components; M; factory; year; upstream datasets; allocation method
required_quality_disclosure	meter coverage; BOM completeness; waste fate; conditional-row applicability; gaps and estimates
update_trigger	Material change in product configuration, materials, energy mix, or manufacturing process

11. Data Sources

Source id	Type	Reference	Used for
un-cpc-3-2025	official_guidance	United Nations Statistics Division, CPC Version 3.0 Structure, 30 June 2025, https://unstats.un.org/unsd/classifications/Econ/Download/In%20Text/CPC_Ver_3.0_Structure_30Jun2025.csv	Product classification identity
greening-2013	literature	Benjamin Paul Greening, Life cycle environmental and economic sustainability assessment of micro-generation technologies in the UK domestic sector, 2013, University of Manchester, https://pure.manchester.ac.uk/ws/portalfiles/portal/54548470/FULL_TEXT.PDF	Manufacturing processes and candidate materials from Chapter 8, Tables 70–71; no general ranges