Refrigerator and heat-pump performance
A heat pump moves heat as well as consuming work.
Key knowledge
For a cyclic device extracting heat Q_c>0 from a cold reservoir and delivering Q_h to a hot one with work input W>0, Q_h=Q_c+W. Refrigerator coefficient of performance is Q_c/W; heat-pump coefficient is Q_h/W=COP_R+1. For two reservoirs with T_h>T_c>0, reversible limits are T_c/(T_h−T_c) and T_h/(T_h−T_c). A coefficient above one does not create energy.
Values and equations
Q_h=Q_c+W; COP_R=Q_c/W≤T_c/(T_h−T_c); COP_HP=Q_h/W≤T_h/(T_h−T_c)
- Q_h,Q_c,W
- Heat delivered, heat extracted and input work per cycle J
- T_h,T_c
- Hot/cold reservoir temperatures K
- COP_R,COP_HP
- Refrigerator and heat-pump performance coefficients 1
Conditions and scope
- Cyclic operation between the two stated reservoirs; Q_c,Q_h,W are positive magnitudes with the displayed balance.
- The reversible limits assume no other reservoirs or energy inputs and use thermodynamic temperatures. Real seasonal performance includes changing operating conditions and auxiliary loads, outside this ideal cycle.
Sources · 2
References
Sources retain their recorded scope. A source link alone does not establish verification of every statement.
Samuel J. Ling, Jeff Sanny and William Moebs — OpenStax, Rice University, University Physics (2016)2 sources
- University Physics Volume 2, §4.3: refrigerators and heat pumpsSamuel J. Ling, Jeff Sanny and William Moebs — OpenStax, Rice University, University Physics (2016)Textbook chapter
- University Physics Volume 2, §4.6: entropySamuel J. Ling, Jeff Sanny and William Moebs — OpenStax, Rice University, University Physics (2016)Textbook chapter
Evidence and review
Read §4.3 refrigerator/heat-pump coefficients4.3–4.4 and §4.6 reversible two-reservoir ratio. Bounds are a disclosed consequence of the existing second law/Carnot relation; no practical-device rating is inferred.
2026-10-10 · /root/audit_life_earth_chemistry — independent Chemistry/Life/Earth editor. Independent AI editorial review of this entry's statements, equations, applicability conditions and source coverage. Source checks apply to these claims within their stated limits.
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- foundation-physics-refrigerator-heat-pump
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- foundations-refresh.1
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