ACTUAL REFRIGERATION SISTEM PADA PH DIAGRAM By MOH. ARIS AS’ARI, S.Pd REFRIGERATION AND AIR CONDITIONING TECHNICAL SKILL PROGRAM SMKN 1 CIREBON Visit us on : refacsmkn1cirebon.wordpress.com

PERBANDINGAN SATURATED CYCLE DAN SUPERHEAT-SUBCOOLED CYCLE daerah liquid subcooled daerah perubahan fasa (liquid+vapor) daerah vapor superheat DIGAMBAR

PH DIAGRAM SUPERHEAT CYCLE daerah perubahan fasa (liquid+vapor) daerah vapor superheat DIGAMBAR

Contoh soal Superheat Cycle Diketahui setelah hasil pengukuran pada suatu sistem refrigerasi yang diberikan pengkondisian panas lanjut pada pipa suction didapat data sebagai berikut : Plot-kan pada PH diagram R-134a dan carilah : RE Total Heat Reject at Condenser Heat of Compression THp Coeffecient of Performance No Lokasi Pengukuran Tekanan (psia) Temperatur (F) 1 Evaporator In 20 2 Superheated Suction line 50 3 Kompresor Out 200 189 Kondenser In 125 4 Liquid line

DIGAMBAR

Solusi! a. Refrigeration Effect hb – ha = 116 – 55 = 61 Btu/lb b. Heat of compression (qw) hc – hb = 138 – 116 = 22 Btu/lb c. Total Heat Reject at Condenser hc – he = 138 – 55 = 83 Btu/lb d. THp untuk mencari Thp maka cari dulu 𝑚 dimana 𝑚 = 𝑄 𝑒 𝑅𝐸 = 200 𝐵𝑡𝑢/ min 𝑡𝑜𝑛 50 𝐵𝑡𝑢/𝑙𝑏 = 3,27 lb/min ton maka Thp = 𝑤 33,000 = 𝐽 × 𝑄 𝑤 33,000 = 778 × 𝑚 × 𝑞 𝑤 33,000 = 778 ×3,27 × 22 33,000 = 1,69 hp Coeffecient of Performance 𝑅𝐸 𝑞 𝑤 = 61 22 =2,77

PH DIAGRAM SUBCOOLED CYCLE daerah liquid subcooled daerah perubahan fasa (liquid+vapor) DIGAMBAR

CONTOH SOAL SUBCOOLED CYCLE! Diketahui setelah hasil pengukuran pada suatu sistem refrigerasi didapat data sebagai berikut : Plot-kan pada PH diagram R-134a dan carilah : RE Total Heat Reject at Condenser Heat of Compression THp Coeffecient of Performance No Lokasi Pengukuran Tekanan (psia) Temperatur (F) 1 Evaporator In 20 2 Suction line 3 Kompresor Out 200 140 Kondenser In 125 4 Subcooled Liquid line 85

DIGAMBAR

Solusi! a. Refrigeration Effect hb – ha = 105 – 40= 65 Btu/lb b. Heat of compression (qw) hc – hb = 125 – 105 = 20 Btu/lb c. Total Heat Reject at Condenser hc – he = 125 – 40= 85 Btu/lb d. THp untuk mencari Thp maka cari dulu 𝑚 dimana 𝑚 = 𝑄 𝑒 𝑅𝐸 = 200 𝐵𝑡𝑢/ min 𝑡𝑜𝑛 65 𝐵𝑡𝑢/𝑙𝑏 = 3,07 lb/min ton maka Thp = 𝑤 33,000 = 𝐽 × 𝑄 𝑤 33,000 = 778 × 𝑚 × 𝑞 𝑤 33,000 = 778 ×3,07 × 20 33,000 = 1,4 hp Coeffecient of Performance 𝑅𝐸 𝑞 𝑤 = 65 20 =3,25

PH DIAGRAM SUBCOOLED-SUPERHEAT CYCLE daerah liquid subcooled daerah perubahan fasa (liquid+vapor) DIGAMBAR

CONTOH SOAL SUBCOOLED-SUPERHEAT CYCLE! Diketahui setelah hasil pengukuran pada suatu sistem refrigerasi didapat data sebagai berikut : Plot-kan pada PH diagram R-134a dan carilah : RE Total Heat Reject at Condenser Heat of Compression THp Coeffecient of Performance No Lokasi Pengukuran Tekanan (psia) Temperatur (F) 1 Evaporator In 20 2 Suction line 50 3 Kompresor Out 200 189 Kondenser In 125 4 Subcooled Liquid line 85

DIGAMBAR

Solusi! a. Refrigeration Effect hb' – ha’ = 115 – 40= 75 Btu/lb b. Heat of compression (qw) hc – hb = 138 – 115 = 23 Btu/lb c. Total Heat Reject at Condenser hc – he = 138 – 40= 98 Btu/lb d. THp untuk mencari Thp maka cari dulu 𝑚 dimana 𝑚 = 𝑄 𝑒 𝑅𝐸 = 200 𝐵𝑡𝑢/ min 𝑡𝑜𝑛 75 𝐵𝑡𝑢/𝑙𝑏 = 2,67 lb/min ton maka Thp = 𝑤 33,000 = 𝐽 × 𝑄 𝑤 33,000 = 778 × 𝑚 × 𝑞 𝑤 33,000 = 778 ×2,67 × 23 33,000 = 1,447 hp Coeffecient of Performance 𝑅𝐸 𝑞 𝑤 = 75 23 =3,26

PERBANDINGAN ANTAR SIKLUS PERFORMANCE INDIKATOR SIKLUS SUPERHEAT SUBCOOLED SUPERHEAT-SUBCOOLED Refrigeration Effect 61 Btu/lb 65 Btu/lb 75 Btu/lb Heat of compression (qw) 22 Btu/lb 20 Btu/lb 23 Btu/lb Total Heat Reject at Condenser 83 Btu/lb 85 Btu/lb 98 Btu/lb THp 1,69 hp 1,4 hp 1,447 hp Coeffecient of Performance 2,77 3,25 3,26