﻿232 
  ANNUAL 
  EEPORT 
  SMITHSONIAN 
  INSTITUTION, 
  192 
  9 
  

  

  either 
  an 
  air-cooled 
  or 
  a 
  water-cooled 
  condenser. 
  The 
  compressing 
  

   of 
  the 
  vapor 
  increases 
  its 
  temperature 
  so 
  that 
  when 
  it 
  reaches 
  the 
  

   condenser 
  the 
  high 
  pressure 
  and 
  the 
  cooling 
  action 
  of 
  the 
  condenser 
  

   are 
  enough 
  to 
  liquefy 
  it. 
  The 
  liquid 
  refrigerant 
  is 
  then 
  directed 
  back 
  

   into 
  the 
  cooling 
  coil 
  in 
  the 
  refrigerator, 
  and 
  the 
  cycle 
  is 
  repeated. 
  

  

  Electrical 
  refrigeration 
  is 
  very 
  similar 
  to 
  a 
  steam 
  heating 
  plant 
  in 
  a 
  

   private 
  residence. 
  There 
  water 
  is 
  boiled 
  over 
  the 
  fire 
  box 
  and 
  the 
  

   steam 
  or 
  water 
  vapor 
  carried 
  by 
  pipes 
  to 
  radiators 
  where 
  on 
  con- 
  

   densing 
  it 
  gives 
  up 
  heat 
  to 
  the 
  room. 
  The 
  condensed 
  steam 
  then 
  

   returns 
  to 
  the 
  boiler 
  where 
  the 
  cycle 
  is 
  repeated. 
  In 
  other 
  words, 
  the 
  

   boiling 
  of 
  the 
  water 
  keeps 
  the 
  boiler 
  relatively 
  cool 
  and 
  thus 
  acts 
  as 
  a 
  

   refrigerating 
  system 
  for 
  the 
  boiler 
  that 
  would 
  otherwise 
  become 
  

   very 
  hot. 
  Heat 
  is 
  transferred 
  from 
  the 
  boiler 
  to 
  the 
  radiators 
  in 
  

   steam 
  heating, 
  while 
  in 
  electrical 
  refrigeration, 
  heat 
  is 
  transferred 
  

   from 
  the 
  refrigerator 
  to 
  the 
  condenser 
  coils 
  in 
  much 
  the 
  same 
  way. 
  

   In 
  steam 
  heating, 
  the 
  water 
  is 
  made 
  to 
  boil 
  by 
  the 
  addition 
  of 
  heat, 
  

   while 
  in 
  electrical 
  refrigeration 
  the 
  liquid 
  is 
  made 
  to 
  boil 
  by 
  the 
  

   reduction 
  in 
  pressure 
  caused 
  by 
  the 
  pump. 
  

  

  The 
  Audifl'ren 
  unit, 
  the 
  first 
  entirely 
  self-contained 
  machine, 
  is 
  

   interesting. 
  It 
  was 
  invented 
  by 
  a 
  French 
  priest, 
  Abbe 
  Audiffren, 
  

   some 
  25 
  years 
  ago, 
  and 
  placed 
  on 
  a 
  commercial 
  basis 
  in 
  this 
  country 
  

   in 
  1911. 
  The 
  unit 
  resembles 
  a 
  large 
  dumb-bell, 
  with 
  one 
  ball, 
  con- 
  

   taining 
  the 
  compressor, 
  revolving 
  in 
  cooling 
  water 
  and 
  with 
  the 
  other 
  

   ball 
  used 
  as 
  an 
  expansion 
  or 
  cooling 
  chamber. 
  This 
  latter 
  ball 
  can 
  

   be 
  immersed 
  in 
  brine 
  or 
  water 
  for 
  cooling 
  purposes. 
  The 
  unit 
  is 
  

   charged 
  with 
  a 
  mixture 
  of 
  sulphur 
  dioxide 
  and 
  lubricating 
  oil 
  at 
  the 
  

   factory, 
  which 
  is 
  sufficient 
  for 
  many 
  years' 
  use. 
  The 
  photograph 
  

   (pi. 
  2, 
  fig. 
  1) 
  shows 
  one 
  of 
  the 
  original 
  French 
  machines 
  that 
  was 
  sent 
  

   to 
  the 
  Heat 
  Measurements 
  Laboratory 
  of 
  the 
  Massachusetts 
  Institute 
  

   of 
  Technology 
  in 
  the 
  summer 
  of 
  1911. 
  This 
  particular 
  machine 
  has 
  

   been 
  in 
  intermittent 
  service 
  for 
  the 
  past 
  18 
  years, 
  operating 
  per- 
  

   fectly, 
  and 
  it 
  has 
  never 
  been 
  opened 
  for 
  inspection 
  or 
  repairs. 
  

  

  "Refrigeration 
  by 
  heat" 
  makes 
  an 
  interesting 
  slogan, 
  but 
  the 
  

   layman 
  rarely 
  understands 
  the 
  principles 
  back 
  of 
  the 
  absorption 
  

   method 
  of 
  refrigeration, 
  although 
  more 
  than 
  50 
  years 
  ago 
  small 
  

   domestic 
  refrigeration 
  units 
  using 
  this 
  principle 
  were 
  sold 
  to 
  the 
  

   public. 
  Cold 
  water 
  absorbs 
  enormous 
  quantities 
  of 
  ammonia 
  gas, 
  

   but 
  if 
  a 
  solution 
  of 
  ammonia 
  and 
  water 
  be 
  heated 
  much 
  of 
  the 
  am- 
  

   monia 
  can 
  be 
  driven 
  out 
  of 
  solution. 
  Ferdinand 
  Carre, 
  many 
  years 
  

   ago, 
  used 
  two 
  containers 
  connected 
  by 
  a 
  pipe, 
  in 
  one 
  of 
  which 
  a 
  strong 
  

   solution 
  of 
  ammonia 
  and 
  water 
  was 
  placed. 
  Adding 
  heat 
  to 
  this 
  

   solution 
  by 
  means 
  of 
  a 
  charcoal 
  fire, 
  the 
  ammonia 
  was 
  driven 
  out 
  

   and 
  as 
  the 
  other 
  container 
  was 
  kept 
  cool 
  by 
  immersing 
  it 
  in 
  water, 
  

   the 
  ammonia 
  gas 
  would 
  condense 
  there 
  in 
  increasing 
  quantities 
  until 
  

   most 
  of 
  the 
  ammonia 
  was 
  evolved. 
  Now, 
  if 
  the 
  weak 
  solution 
  were 
  

  

  