TERMO
TERMODINAMIKA
DINAMIKA
Thermos = Panas
Thermos = Panas
Dynamic = Perubahan
Dynamic = Perubahan
Pada tahun 1901 , Italia penemu Luigi Bezzera
Pada tahun 1901 , Italia penemu Luigi Bezzera datang dengan solusi yang bisadatang dengan solusi yang bisa diterapkan . Pavoni diproduksi mesin-mesin espresso pertama pada tahun 1905 .
diterapkan . Pavoni diproduksi mesin-mesin espresso pertama pada tahun 1905 .
Mesin ini juga bertenaga uap . Namun, uap t
Mesin ini juga bertenaga uap . Namun, uap tidak datang ke dalam kontak dengan kopi . Sebaliknya ,idak datang ke dalam kontak dengan kopi . Sebaliknya , tekanan uap pada bagian atas boiler memaksa air di bagian bawah boiler me
tekanan uap pada bagian atas boiler memaksa air di bagian bawah boiler me lalui kopi bubuk . Kopilalui kopi bubuk . Kopi diselenggarakan dalam kelompok yang terdiri dari portafilter , filter k
diselenggarakan dalam kelompok yang terdiri dari portafilter , filter k eranjang logam dan removableeranjang logam dan removable kuningan gunung , dan kepala brew di mana portafilter me
kuningan gunung , dan kepala brew di mana portafilter me nempel . Pipa dan kelompok yang dirancangnempel . Pipa dan kelompok yang dirancang untuk bertindak sebagai radiator panas , sehingga suhu air bertekanan t
untuk bertindak sebagai radiator panas , sehingga suhu air bertekanan t urun dari 250 ° F ( 120 urun dari 250 ° F ( 120 ° C )° C ) dalam boiler dengan suhu menyeduh benar pada grouphead tersebut . Pr
dalam boiler dengan suhu menyeduh benar pada grouphead tersebut . Pr insip ini bir masih digunakaninsip ini bir masih digunakan dalam kompor mochapots . Karena air bertekanan ,
dalam kompor mochapots . Karena air bertekanan , kopi bisa menjadi tanah halus daripada di birkopi bisa menjadi tanah halus daripada di bir pourover teratur, mengurangi siklus pembuatan bir minimum dari sekitar 4 menit
pourover teratur, mengurangi siklus pembuatan bir minimum dari sekitar 4 menit 30 detik. Mesin30 detik. Mesin espresso dan penggiling kopi yang menyertainya menjadi perlengkapan standar untuk membuat kopi di espresso dan penggiling kopi yang menyertainya menjadi perlengkapan standar untuk membuat kopi di Italia , Perancis Selatan , S
Italia , Perancis Selatan , Spanyol dan Amerika Latin . Di bagian lain dunia, diikuti imigran Italia yangpanyol dan Amerika Latin . Di bagian lain dunia, diikuti imigran Italia yang mempopulerkannya di setiap negara mereka menetap .
mempopulerkannya di setiap negara mereka menetap .
Namun teknologi bergerak, dan metode ini tidak lagi dianggap sebagai khusus espresso ,
Namun teknologi bergerak, dan metode ini tidak lagi dianggap sebagai khusus espresso , meskipunmeskipun mochapots dan bir ditekan uap lainnya terus dipasarkan di bawah nama . Pada 1920-an me
1940-an , insinyur Italia bereksperimen dengan perangkat memompa untuk meningkatkan tekanan 1940-an , insinyur Italia bereksperimen dengan perangkat memompa untuk meningkatkan tekanan pembuatan bir . Yang praktis pertama dikembangkan oleh Cremonesi pada tahun 1938 dan
pembuatan bir . Yang praktis pertama dikembangkan oleh Cremonesi pada tahun 1938 dan diproduksidiproduksi oleh Achille Gaggia pada tahun 1946 . D
oleh Achille Gaggia pada tahun 1946 . Dulu tangan piston bertenaga . Pada mesin jenis ini , teulu tangan piston bertenaga . Pada mesin jenis ini , te kanankanan steam dalam boiler memaksa air ke
steam dalam boiler memaksa air ke dalam silinder , tetapi kemudian bertekanan lebih lanjut dengandalam silinder , tetapi kemudian bertekanan lebih lanjut dengan piston musim semi bertenaga sekitar 8 sampai 9 bar
piston musim semi bertenaga sekitar 8 sampai 9 bar ( 120-135 PSI ) , ( 120-135 PSI ) , atau 8 sampai 9 kali tekanan yangatau 8 sampai 9 kali tekanan yang telah dikembangkan oleh mesin uap. Musim semi yang kekuatan piston dikompresi oleh tuas dipaksa telah dikembangkan oleh mesin uap. Musim semi yang kekuatan piston dikompresi oleh tuas dipaksa turun oleh barista ( Italia untuk barkeep )
turun oleh barista ( Italia untuk barkeep ) - orang yang membuat kopi . Seperti dengan mesin g- orang yang membuat kopi . Seperti dengan mesin g enerasienerasi tua , kelompok-kelompok tuas dirancang untuk mendinginkan air dari boiler suhu pembuatan bir . tua , kelompok-kelompok tuas dirancang untuk mendinginkan air dari boiler suhu pembuatan bir .
Heat Exchanger Machines How They Work
Heat Exchanger Machines How They Work
»
» Coffeetime Contents PageCoffeetime Contents Page »» EquipmentEquipment » Heat Exchanger Machines How They Work» Heat Exchanger Machines How They Work
The Heat Exchanger Espresso Machine - Demystified
The Heat Exchanger Espresso Machine - Demystified
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Also see:
Also see:
In this article I want to
In this article I want to explain how the Heat Exchanger type of espresso machine actuallyexplain how the Heat Exchanger type of espresso machine actually
works. This type of machine is really very sim
works. This type of machine is really very simple, although often people seem to beliple, although often people seem to believe it’seve it’s
much more complicated than it is, especially the mystical
much more complicated than it is, especially the mystical “heat exchanger”. As usual on“heat exchanger”. As usual on
Coffeetime, we like to keep it simple:
Coffeetime, we like to keep it simple:
Let’s first start with an explanation of the
Let’s first start with an explanation of the “Heat Exchanger (HX)”,“Heat Exchanger (HX)”, a very fancy term for a a very fancy term for a
copper tube that passes through hot water. In the picture below, we
copper tube that passes through hot water. In the picture below, we have built one, and ashave built one, and as
the cold water flows through the copper tube, immersed in
the cold water flows through the copper tube, immersed in a container of hot water, it getsa container of hot water, it gets
heated up.
So the HX is really
So the HX is really very simple and it is probably very simple and it is probably clear that the temperature of hot waterclear that the temperature of hot water
exiting the heat exchanger depends on a number of
exiting the heat exchanger depends on a number of thingsthings
How hot the water in the container (boiler) isHow hot the water in the container (boiler) is
The surface area of the copper tube (or to put The surface area of the copper tube (or to put it simply, how long it it simply, how long it is)is)
The temperature of the water when it enters the The temperature of the water when it enters the copper tubecopper tube
How fast the water flowsHow fast the water flows
The espresso machine designers will have to consider these factors in designing a machine
The espresso machine designers will have to consider these factors in designing a machine
that is able to produce enough hot water, without
that is able to produce enough hot water, without it being too hot it being too hot and to minimise theand to minimise the
requirements of a cooling flus
requirements of a cooling flush. Now we have the “complexities of the h. Now we have the “complexities of the very simple devicevery simple device
that is the “Heat Exchanger” out of the
that is the “Heat Exchanger” out of the way, lets move on to a simpliway, lets move on to a simplified diagram of thefied diagram of the
insides of a real espresso machine
The diagram has been divided into 3 coloured sections for clarity
The diagram has been divided into 3 coloured sections for clarity (click to enlarge).(click to enlarge).
Yellow Section
Yellow Section
This section is what could be termed the
This section is what could be termed the cool side of the cool side of the machinemachine; it will contain the; it will contain the
cold water tank (or possibly mains water inlet on a pl
cold water tank (or possibly mains water inlet on a plumbed machine). Its task is to provideumbed machine). Its task is to provide
water at the correct pressure to the rest of
water at the correct pressure to the rest of the espresso machine. The pump can be either athe espresso machine. The pump can be either a
Vibration pump, or in the case of a
Vibration pump, or in the case of a machine like my Izzo Alex, a machine like my Izzo Alex, a rotary pump. Its solerotary pump. Its sole
purpose is to pump water at high
purpose is to pump water at high pressure (9 or 10 bar).pressure (9 or 10 bar).
Note: Vibration pumps are unregulated and deliver water at a
Note: Vibration pumps are unregulated and deliver water at a pressure of 15 bar (much toopressure of 15 bar (much too
high for espresso). Rotary pumps have their
high for espresso). Rotary pumps have their own internal pressure regulation and can own internal pressure regulation and can bebe
regulated to deliver water directly at 9 bar.
regulated to deliver water directly at 9 bar.
The water is drawn from the cold water tank, into the
The water is drawn from the cold water tank, into the vibration pump, and through a devicevibration pump, and through a device
ca
called an OPV (pressure release valve) which lowers it’s pressure. You will notice that thislled an OPV (pressure release valve) which lowers it’s pressure. You will notice that this
OPV has a tube leading back to
OPV has a tube leading back to the cold water tank, because to regulate water pressurethe cold water tank, because to regulate water pressure
down to 9 or 10 bar,
down to 9 or 10 bar, it has to allow some it has to allow some of the water back to the tank rather of the water back to the tank rather than into thethan into the
machine (see
machine (see OPV articleOPV article for more information on how the OPV works).for more information on how the OPV works).
The water now passes from the OPV to the rest
The water now passes from the OPV to the rest of the machine; this water can now onlyof the machine; this water can now only
exert a maximum static pressure of 9 or 10
exert a maximum static pressure of 9 or 10 bar. It next comes to something bar. It next comes to something called ancalled an
“Autofill Solenoid”. The “Auto
Water is directed to the E61 group Water is directed to the E61 group (via the HX) for making coffee (normally in this(via the HX) for making coffee (normally in this position)
position)
Water is directed into the main Water is directed into the main boiler to refill e.g. after boiler to refill e.g. after steaming, or using hot water.steaming, or using hot water. The function of this solenoid, as you may have guessed, is simpl
The function of this solenoid, as you may have guessed, is simply to ensure the main boilery to ensure the main boiler
can fill when needed, without pushing water through the E61 group.
can fill when needed, without pushing water through the E61 group.
Our water leaves the yellow section, able t
Our water leaves the yellow section, able to exert a maximum static pressure of 9o exert a maximum static pressure of 9
or 10 bar, fine for making coffee
or 10 bar, fine for making coffee and at a high enough pressure to fill and at a high enough pressure to fill our boilerour boiler
(which is usually kept at around 1.3 bar).
(which is usually kept at around 1.3 bar).
Red Section
Red Section
This can be termed the hot
This can be termed the hot side of the machineside of the machine, it’s where the water get, it’s where the water gets heated,s heated,
steam is produced and everything is prepared for coffee making.
steam is produced and everything is prepared for coffee making.
The main component of this section is the
The main component of this section is the Boiler, as you can see it Boiler, as you can see it is full of hot water andis full of hot water and
steam. It can do this because the boiler
steam. It can do this because the boiler is like a pressure cooker and inside iis like a pressure cooker and inside it’s at a ht’s at a higherigher
pressure than atmospheric. In fact the boiler is usually at around 1.2 bar. This means we
pressure than atmospheric. In fact the boiler is usually at around 1.2 bar. This means we
have water at around 124C (yes hotter than boiling which i
have water at around 124C (yes hotter than boiling which is 100C) and an area of steams 100C) and an area of steam
above the hot water. The boiler is
above the hot water. The boiler is maintained at this pressure by the litmaintained at this pressure by the little pressurestattle pressurestat
which switches the heating element on/off as required to maintain 1.2
which switches the heating element on/off as required to maintain 1.2 bar.bar.
These
These pressurestatspressurestats are usually adjustable, via an adjuster on top (using a are usually adjustable, via an adjuster on top (using a screwdriver.).screwdriver.).
When we open the steam tap, steam comes out When we open the steam tap, steam comes out and the pressure in the boiler drops,and the pressure in the boiler drops, this causes the water to instantly boil, producing more steam…very simple
this causes the water to instantly boil, producing more steam…very simple
When we open the hot water tap, steam pressure forces the water outWhen we open the hot water tap, steam pressure forces the water out The autofill probe is just
The autofill probe is just in the water, but when the water level in the water, but when the water level drops as in steaming ordrops as in steaming or
drawing hot water, it senses this drop in
drawing hot water, it senses this drop in level and tells the Control Board (brain). The brainlevel and tells the Control Board (brain). The brain
then switches on the pump and sets the autofill solenoid to the fill the boiler position. Once
then switches on the pump and sets the autofill solenoid to the fill the boiler position. Once
the water level reaches the probe, the pump
the water level reaches the probe, the pump switches off and the autofill solenoid goes backswitches off and the autofill solenoid goes back
to the making coffee position.
to the making coffee position.
You can clearly see the HX tube within
You can clearly see the HX tube within the boiler and this works no differently to the the boiler and this works no differently to the simplesimple
diagram given earlier.
diagram given earlier.
Tan (or Coffee Coloured) Section
Tan (or Coffee Coloured) Section
This is the business end of theThis is the business end of the machine, the part you normally see and interact with. All machine, the part you normally see and interact with. All thethe
previous wizardry was to deliver hot water at about 93-96C and 9
previous wizardry was to deliver hot water at about 93-96C and 9 bar (140 psi) to this bar (140 psi) to this partpart
of the machine for making coffee. Move l
of the machine for making coffee. Move lever up, pump starts, water passes through HXever up, pump starts, water passes through HX
into group at 9 bar, i
into group at 9 bar, into portafilter and through coffee….mmmm espresso!nto portafilter and through coffee….mmmm espresso!
The only slight complexity here is shown in
The only slight complexity here is shown in the area marked by the green dashed line.the area marked by the green dashed line. TheThe
E61 thermosyphon (link)
circulate through the E61 group to keep it
circulate through the E61 group to keep it hot (this increases temperature stability duringhot (this increases temperature stability during
the shot). You can read much more about it in
the shot). You can read much more about it in thethe E61 thermosyphon articleE61 thermosyphon article..
Lastly the poor old control board…well it’s box of
Lastly the poor old control board…well it’s box of electronics and controls the pump, waterelectronics and controls the pump, water
level, autofill solenoids and even has a protective circuit
level, autofill solenoids and even has a protective circuit that prevents the heating elementthat prevents the heating element
coming on if the boil
coming on if the boiler needs filling. It does a fer needs filling. It does a few other fancy functions at switch on, but it’sew other fancy functions at switch on, but it’s
really a simple device. They are sometimes called level
really a simple device. They are sometimes called level controllers and are usually made bycontrollers and are usually made by
Giemme or Gicar for prosumer machines. They are not meant to
Giemme or Gicar for prosumer machines. They are not meant to be user serviceable and ifbe user serviceable and if
they go wrong are usually replaced. However often a fault is a
they go wrong are usually replaced. However often a fault is a simple transformer that runssimple transformer that runs
one of the solenoids and these can sometimes be purchased cheaply for a
one of the solenoids and these can sometimes be purchased cheaply for a few pounds andfew pounds and
replaced using a soldering iron.
replaced using a soldering iron.
How it How it Works Works
