( ( Inside ( the ( heat pump ) ) ) ( , ( ( a ( sealed ( refrigerant system ) ) ) ( ( is ( the ( heat-exchange medium ) ) ) . ) ) ) )
(ROOT (S (PP (IN Inside) (NP (DT the) (NN heat) (NN pump))) (, ,) (NP (DT a) (JJ sealed) (NN refrigerant) (NN system)) (VP (VBZ is) (NP (DT the) (JJ heat-exchange) (NN medium))) (. .)))
Inside the heat pump, a sealed refrigerant system is the heat-exchange medium.
(ROOT (S (NP (DT A) (JJ sealed) (, ,) (JJ vacuum-insulated) (NN reaction) (NN flask)) (VP (VBZ approximates) (NP (NP (DT the) (NN condition)) (PP (IN of) (NP (NP (DT a) (VBN isolated) (NN system)) (, ,) (SBAR (WHPP (IN in) (WHNP (WDT which))) (S (NP (CC neither) (NP (NN matter)) (CC nor) (NP (NN heat))) (VP (MD can) (VP (VB be) (VP (VBN exchanged) (PP (IN between) (NP (NN system) (CC and) (NNS surroundings)))))))))))) (. .)))
A sealed, vacuum-insulated reaction flask approximates the condition of a isolated system, in which neither matter nor heat can be exchanged between system and surroundings.