( ( ( The differences ) ( between ( ( the engine ) ( described ( ( above ( and ( ( a ( Stirling machine ) ) ( employed ( as ( ( a refrigerator ) ( are ( that ( ( compression ( volume 22 ) ) ( ( is typically ) ( in ( ( thermal communication ) ( with ( ambient ( temperature ( and ( expansion volume ) ) ) ) ) ) ) ) ) ) ) ) ) ) ) ) ) 24 ) ) ) ) ) ( ( is ( connected ( to ( ( an ( external ( cooling load ) ) ) ( -LRB- ( ( not shown ) -RRB- ) ) ) ) ) ) . ) )
(ROOT (S (NP (NP (DT The) (NNS differences)) (PP (IN between) (NP (NP (DT the) (NN engine)) (VP (VBN described) (PP (IN above) (PRN (CC and) (S (NP (DT a) (NNP Stirling) (NN machine)) (VP (VBN employed) (SBAR (IN as) (S (NP (DT a) (NN refrigerator)) (VP (VBP are) (SBAR (IN that) (S (NP (NNP compression) (NN volume) (CD 22)) (VP (VBZ is) (ADVP (RB typically)) (PP (IN in) (NP (NP (JJ thermal) (NN communication)) (PP (IN with) (NP (JJ ambient) (NN temperature) (CC and) (NN expansion) (NN volume)))))))))))))) (NP (CD 24))))))) (VP (VBZ is) (VP (VBN connected) (PP (TO to) (NP (NP (DT an) (JJ external) (VBG cooling) (NN load)) (PRN (-LRB- -LRB-) (VP (RB not) (VBN shown)) (-RRB- -RRB-)))))) (. .)))
The differences between the engine described above and a Stirling machine employed as a refrigerator are that compression volume 22 is typically in thermal communication with ambient temperature and expansion volume 24 is connected to an external cooling load (not shown).
(ROOT (S (NP (DT The) (NN term) (JJ thermal) (NN expansion)) (VP (VBZ is) (VP (VBN used) (S (VP (TO to) (VP (VB describe) (NP (NP (DT the) (NN change)) (PP (IN in) (NP (NN size) (CC or) (NN volume))) (PP (IN of) (NP (NP (DT a) (VBN given) (NN mass)) (PP (IN with) (NP (NN temperature))))))))))) (. .)))