SCIENCE · INVESTIGATE AND EXPLAIN

Fix the delivered service before comparing lifecycle burdens

A product is not its service. A heater comparison should specify useful heat delivered at the required temperature, reliability and duration, rather than compare one appliance or one unit of electricity. This functional unit makes alternatives answer the same need. Their material, manufacturing, operating and end-of-life boundaries must then be made comparable.

Learning outcome: Compare COP 2 and 4 at intensity 0.1, then increase intensity to 0.7. Keep the functional unit fixed and identify an omitted lifecycle term that could change the ranking.

Starting recap

Fix the useful service, lifecycle boundary and scenario; distinguish a conditional model result from an observed causal improvement.

All lessons are open directly. Your saved experiments remain when you leave and return.

Try

At COP 3 and intensity 0.3 kg CO₂e/kWh, heat-pump electricity is 33333.33 kWh and total burden 14000 kg CO₂e. Resistance total is 31000. The difference is −17000; heat-pump service intensity is 0.14 kg CO₂e/kWh useful heat.

Open the experiment

Predict

Why may a heat pump have COP above one?

Your prediction and reason

Experiment

Compare COP 2 and 4 at intensity 0.1, then increase intensity to 0.7. Keep the functional unit fixed and identify an omitted lifecycle term that could change the ranking.

Compare emissions per delivered heat service

Worked teaching model · synthetic values · Original lifetime service 100000 kWh useful heat. Resistance heater electricity equals service, embodied burden 1000 kg CO₂e. Heat pump electricity=service/COP, embodied burden 4000 kg CO₂e. Same lifetime, heat quality and boundary; no discounting, refrigerant leakage or performance drift unless separately added.

Heat-pump seasonal COP: 3 heat/electricity ratio Electricity emissions intensity: 0.3 kg CO₂e/kWh

Reset keeps your prediction, captures and practice history.

Original synthetic system; units differ by row
Quantity	Value	Unit
Useful lifetime heat	100000	kWh heat
Heat-pump electricity	33333.33	kWh electricity
Resistance lifecycle emissions	31000	kg CO₂e
Heat-pump lifecycle emissions	14000	kg CO₂e
Heat-pump minus resistance	-17000	kg CO₂e
Heat-pump intensity per heat service	0.14	kg CO₂e/kWh heat

The functional unit fixes the useful service before comparing inputs and lifecycle burdens.

COP is heat delivered divided by electricity, not an efficiency bounded by one: environmental heat is also transferred. Common lifetime and temperature conditions matter; omitted leakage or unequal durability would require new boundary terms.

Predict, change one control, and save contrasting captures. Reconstruct the balance with units; then explain a process the ledger deliberately leaves out. Display precision is not measurement precision.

The functional unit fixes the useful service before comparing inputs and lifecycle burdens.

Observation to attach to a capture

Captures preserve recipes and replay their calculated results. They are synthetic model evidence, not physical measurements.

Understand

Define the useful service

Construct the comparable ledger

A heat pump transfers environmental heat as well as converting electrical input. Its coefficient of performance is useful heat divided by electricity; a value above one does not create energy. Seasonal performance varies with temperature and operating conditions. The original packet fixes lifetime useful heat at 100000 kWh, resistance embodied emissions at 1000 kg CO₂e and heat-pump embodied emissions at 4000 kg CO₂e.

Interpret the competing metrics

Operational emissions equal electricity multiplied by a supplied average emissions intensity. Total heat-pump emissions are 4000+100000×intensity/COP; resistance total is 1000+100000×intensity. Dividing by common useful heat gives a service-normalized lifecycle measure. An average inventory factor is not automatically the marginal emissions caused by a new installation.

Challenge the boundary and scenario

Refrigerant leakage, replacements, unequal durability, climate-dependent performance and future electricity changes could alter the comparison. Name them rather than silently assign zero impact. The model tests arithmetic and boundary sensitivity, not a household purchasing recommendation or a claim that one technology dominates every impact category.

Worked original packet

Investigation

Compare COP 2 and 4 at intensity 0.1, then increase intensity to 0.7. Keep the functional unit fixed and identify an omitted lifecycle term that could change the ranking.

Changed-case transfer

At COP 2 and intensity 0.1, calculate both totals. How much extra heat-pump lifecycle burden would erase its advantage?

Feedback

Heat pump 4000+5000=9000; resistance 1000+10000=11000 kg CO₂e. An additional 2000 kg CO₂e on the heat-pump boundary would make totals equal, assuming no other change.

Sources and evidence boundary

Original prose, numerical packets and exercises. Primary method/mechanism source, checked 30 October 2026. Supplied values are not measured operating data, universal coefficients or recommendations. No physical equipment work, chemical application, organism manipulation or water extraction is requested. Retain first reasoning and critique in the course workspace; public feedback is practice, not independent assessment.

DOE heat-transfer mechanism; only the mechanism is used, not a current savings estimate.

Apply

Public practice checks a specific claim. It does not establish independent mastery.

At COP 2 and intensity 0.1, calculate both totals. How much extra heat-pump lifecycle burden would erase its advantage?

Your explanation and limitations

Continue

Completion requires a saved prediction, at least one capture and a reflection. Presence checks do not grade your reasoning.

Skipping retains experiments and awards no mastery.

Previous: Separate a changed input from a delayed environmental stock Next: Distinguish allocation conventions from avoided emissions

Save a science backup or import one

Science work is stored locally in this browser, separately from mathematics and AI. It does not sync automatically. Use this science-only backup; this checkout's older all-subject export does not include science.

A legacy file is available only when the complete snapshot fits the 36 MB limit. For larger snapshots, prepare a complete file set below; never discard notebooks to make a smaller file.

Choose a science backup (maximum 36 MB)

Matching imported notebook drafts replace their current drafts. Omitted lessons and known first attempts remain. Export your current work first if you want to retain both drafts.

Complete file sets and course backups

A file set can hold more work than one science file. Keep its manifest and every part together. Each file is limited to 36 MB. This format needs this version of LearnAI or a compatible newer version; older versions can use only the legacy single-file backup above.

Export scope

The set includes every saved science course and global continuation at this moment. Later edits need a new export. A conflicting tab exports its own visible work, which may differ from saved work in another tab.

Choose the manifest and all parts together

0 file(s) selected. File order and filenames do not determine identity. Missing, changed or conflicting parts block the entire restore; no good part is applied by itself.

Science storage: loading. No account or remote computation is required.