Heat pump

Example

Use in Lemonergy

Select spatial detail for the question.

This is a reference concept. No executable Lemonergy block has been verified for this term.

Connected concepts

Related concepts from the knowledge graph. Connections show context, not cause and effect. Hover or focus a linked term for its definition.

Battery heating

Warming a cold battery before charging or use. External methods use electric heaters, a heat pump or warm coolant; internal methods heat the cell through its own resistance with alternating current or rapid charge–discharge pulses. Experimental self-heating cells embed a nickel foil that takes them from −20 °C to 0 °C in about 20 seconds.

Chiller

A heat exchanger in which evaporating refrigerant from the air-conditioning circuit cools the battery coolant below ambient temperature. A radiator can only bring coolant close to outside air temperature; the chiller is what lets a pack fast-charge on a 35 °C day. Stationary storage containers use packaged chiller units for the same job.

Preconditioning

Warming or cooling the battery to its preferred temperature before a fast charge or a hard drive, using the vehicle’s own heaters and pumps. Navigating to a charger triggers it in many cars, because a cold pack cannot accept high current safely.

Range

How far an electric vehicle travels on a full charge: usable energy divided by consumption per kilometre. Cold weather, speed and heating cut it, and the gap between official and real range is usually consumption, not battery capacity.

Refrigerant loop

A closed vapour-compression circuit: a compressor raises refrigerant pressure and temperature, a condenser rejects that heat to air, an expansion valve drops the pressure, and an evaporator absorbs heat as the refrigerant boils. Batteries draw on it through a chiller or through refrigerant plates that act as evaporators; R1234yf and CO₂ (R744) are the usual refrigerants.

Thermoelectric cooling

Solid-state heat pumping by the Peltier effect: current through junctions of semiconductor elements moves heat from one face to the other, and reversing the current reverses the direction. Peltier modules hold small test cells at a set temperature in laboratory fixtures, but their efficiency, usually a coefficient of performance below 1, is too low for vehicle packs.

References & further reading

Further reading on this topic

These sources provide broader context; they are not presented as citations for every statement in this entry.

1. A General Energy Balance for Battery Systems

   Dawn Bernardi, Ellen Pawlikowski, John Newman · Journal of The Electrochemical Society · 1985

   Topic background · Battery energy balance and irreversible and reversible heat contributions. Reduced thermal models require explicit assumptions and current-sign conventions.

2. University Physics Volume 2, §1.6: Mechanisms of Heat Transfer

   OpenStax, Rice University

   Topic background · Conduction, convection, radiation and thermal resistance.