A/C and heating efficiency

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Energyisfree

New member
Joined
Apr 12, 2014
Messages
1
Does the Leaf air conditioning have a compressor or does it use so-called space-age cooling fins?

Is the waste heat from the inverter for the motor reused as cabin heat during winter for example?
 
Energyisfree said:
Does the Leaf air conditioning have a compressor or does it use so-called space-age cooling fins?
Is the waste heat from the inverter for the motor reused as cabin heat during winter for example?
The LEAF's air conditioner uses a compressor "as usual", although I don't understand why that would exclude adding fins to the heat exchange surfaces. Beginning with the 2013 model year, the LEAF's air conditioning components were rearranged, as owners had been imploring, to serve as a heat pump for cooling OR heating the cabin, though according to the claims of several here, the arrangement doesn't cool as effectively as the "plain" air conditioner did (I don't understand why not though).

Welcome as reclaiming the drive system's heat would be (and even more so, extracting heat from the battery!), Nissan apparently deems that uneconomic.
 
The system is a Renault devised system (AFAIK), first appearing in the Zoe. It consists of having two matrices (one condensing, one evaporating) in the cabin space and one at the front (which can function in either evaporating or condensing modes).

In air con mode, the working fluid operates as a usual air con system, with evaporation of the working fluid happening in a matrix in the cabin, and condensing again at the front matrix. The cabin condenser is bypassed.

In the heating mode, valves route the working fluid to the second of the cabin matrices which is a condenser matrix. This generates heat. The evaporative matrix can either be bypassed completely, or can work too to provide a/c and heat together. In the heating mode, the front matrix becomes an evaporative matrix. The pressure of the working fluid is regulated by more valves that set the temperature/pressure at a point at which it will evaporate, rather than condense, in the front matrix.

So the 'only' difference is that there are two cabin matrices, and a number of valves to direct the flow and regulate the pressure of the working fluid. The flow direction of the working fluid is not reversed at any point.
 
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