It is very important to know the difference between thermal oil and steam when you
select the heating system. This means that
there are many advantages and disadvantages which should be absolutely known.
For an example please see also this detailed report with technical informations Laundry Installation Technology
We want to reach a minimum of energy use with an optimum of control and operational safety.
For decades high pressure steam is known everywhere for the heating of the machines. An example of basic significance is the selection of the appropriate heating medium. Until now, for large laundries, the high - pressure steam plant was unchallenged and adequately popular everywhere. A satisfactory heat transmission and application on all laundry machineries were the positive features of this traditional old technique.
But the following disadvantages must be taken into account and are unavoidable when using high pressure steam:
Easy for use:
The machine manufacturer has to pay attention to the different points, which are once known easy to do. By the decision of the right system he should not forget that the customer should profit and not the people who wants to install only the steam heating plant.
There are many Regiomat thermal oil heating plants which are installed until today in textile, food, chemistry and packaging branches because these people has known the advantages of thermal oil and they have only made a positive experience.
On/Off starting by pressing one switch, easy and fast, also after a
long break because the heater, the pipelines and the machines are filled with thermal oil
which protects the whole installation- therefore less maintenance works.
bigger duration of life
Behaviour of pressure:
It is not possible to notice all technical advantages and disadvantages in this report. But a very important point is that something about the heat transfer/transmission. When using steam the best heat transfer happens when steam condense but when using thermal oil the best heat transfer happens by a fast flow rate. The manufacturer which constucts the machines has to consider these different heat transfers.
To work with a high pressure steam generator with 14 bar for heating the mangles and tumblers does not make sence. Because there is a lot of condensate which is very expensive if you want to recover it. For a direct heating of the machines it is necessary to reduce the steam pressure from 14 bar back to 3 bar, which does not make sence.
A direct heating for the mangles and tumblers with thermal oil is better and there is no special recovery necessary
Washing machines with a water temperature of 95°C could be heated indirectly with thermal oil by using a low pressure steam generator.
A steam pressure of 3 bars is easy to produce without any problems, because there is no condensate and it is no water treatment necessary
When once installed a thermal oil system in a laundry the advantages will be shown. All machines could be revised from steam to thermal oil so it is possible to use also the occasion machines. To use the old steam system for thermal oil is possible but it does only make sence when a revise of the whole plant has to be done.
The hotel "Grandhotel Tschuggen" in Arosa ( Switzerland ) worked for 18 years with steam and then in 1990 the whole system was prepared to work with thermal oil. The seasonal interruptions of the old system have made that the pipelines and its components were full of corrosions.Grand Hotel Tschuggen, Arosa:
This is a popular example to show how easy it is to change the system. But more important is that the owner of this system has a lot of advantages which he had not before. One most advantage is the easy use of a thermal oil heating plant and the energy savings. In the end of the season he can switch off the thermal oil heating plant and at the new beginning of a season he can switch on the heating plant. There is no danger of high pressure steam and the condensate, no energy losses, no expensive water treatment, no chemical consumption, no daily maintenance works, no inspection obligations and no corrosions. the lifetime of the thermal oil heating plant will be much more longer.
Regiomat has installed a lot of thermal oil heating plants in different hotels and hospital all over the world. Regiomat could learn of this experience which are also usefull for the machine suppliers. Today there are special pumps, valves etc. on the market which are specially built for thermal oil with a high quality.
This development was intersting for the Swiss Army which has installed until today three big laundries. A comparison between the plant in Monte Ceneri with high pressure steam and Sursee with thermal oil is significant. In the year 2000 it was built a thermal oil heating plant in Payerne. See also the reference report for the military laundry in Payerne-Switzerland.
We recommend a thermal oil heating for all different uses in industries . The operational safety (also for unskilled personal) and a longer life time are the advantages of a modern, "no-pressure ", thermal oil heating! Due to the manifold use in the most different industrial branches it can be ascertained today that a well-planned and properly installed thermal oil plant offers specific advantages for the user. The heat consumers are directly connected to the thermal oil heating system which is suitable for freely adjustable temperatures of up to 350°C. Important units are equipped with secondary circuits, consisting of injection valve and secondary pump etc., so that the operating temperature can be optimally regulated. A centralised thermal oil heating system with closed circuit operates fully automatic, safely without supervision and can be used for general purposes. In close cooperation with machine manufacturers, Regiomat is involved in the planning and construction of entire installations, including delivery, assembly and commissioning as well as care-taking of such thermal oil heating systems.
Regiomat guarantees a controllable flow through the heater. The thermal oil has the possibility to expand over a non-turn-off pipeline between the heater and the expansion vessel. The nitrogen in the expansion vessel guarantees the necessary pressure balance and protects the thermal oil from the oxygen in the air. This is the reason why the thermal oil doesn't oxidize even when we have high temperatures. So you have a system which works for more than 15 years without any problems.
The necessary safety installations are:
3. Circulation pump
4. Expansion vessel
5. Nitrogen system
6. Gas collection bottle
7. Autom. centralized air
8. Cock with cap
9. Shut-off valves
|11. Vibration absorber
14. Safety valve
15. Vacuum breaker
18. Thermostat flue gas
19. Flow control
20. Thermostat main pipe
21. Temperature controller
23. Temperature gauge
24. Level switch
25. Rupture disk
26. Level control
27. Filling pump
28. Safety valve
Download this diagram here
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