Peter von Rittinger’s Steam Pump (AKA: The First Heat Pump)

Peter von Rittinger’s biography reads like a Victorian novel, and his invention was a text-book example of innovation triggered by scarcity.

Born 1811, he was poor and became an orphan early. Yet he was able to study mathematics and physics as his secondary education had been financed by the Piarist Order. He also studied law and mining. Immediately after having graduated he was appointed as inspector in an iron ore processing plant (stamping mill), and later called a pioneer in that field and accountable for several inventions.

1850 Rittinger became ‘Sectionsrat’ (head of a division) in the Ministry of Agriculture and Mining in Vienna. He was knighted in 1863, so quoting all his titles as a public servant in the higher echelons of the Austro-Hungarian empire he was: k. k. Sectionsrath Oberbergrath Ritter von Rittinger. (Detailed biographies: DE / EN).

Peter von Rittinger Yet it seems even as an administrator he was still a hands-on tinkerer. He developed a process for harvesting salt from brine at Saline Ebensee in Upper Austria – saving 80% of input energy compared to other processes used at this time.

In the mid of the 19th century saltworks in Austria had been dependent on wood available locally. Having cut down forests, they ran out of fuel. Railway tracks have not been built yet, and fossil fuels had not yet been available. The ecological footprint had to be much closer to the physical area than today.

But Sectionsrath Rittinger was creative with what was available. In History of Heatpumps, Martin Zogg writes:

One of the main applications [of mechanical vapor compression] is the salt production from salt brine. In order to get 1 kg of salt there have to be evaporated about 3 kg of water, which illustrates the enormous energy demand of such processes. Whole forests had been cleared for this purpose.
Peter von Rittinger … was the first to try the realisation of this idea on a pilot scale. …. He designed and installed the first known pilot heat pump for heating only with a capacity of 14  kW, … The start-up of Rittinger’s “steam pump” was in 1857.

This is the title page of Rittinger’s publication of 1855:

Rittinger, Abdampfverfahren, 1855. Title page.Translating about to:

Theoretical-practical treatise
on a novel evaporation process
applicable to all varieties of liquids
using one and the same amount of heat
which – for this purpose –
is set into perpetual circular motion by water power.
Taking into account the salt boiling process specifically.

I have created this simplified figure from the description in his paper:

Rittinger, Steam Pump, called the first heat pump.
Simplified sketch (by elkement) showing the principles of Peter von Rittinger’s steam pump as described in his original paper. The vessel had to be opened to remove the salt which had precipitated in the upper part of the vessel (called a brine ‘pan’ in German) and water accumulated in the lower part (‘double bottom’).

Salt brine is feed into the upper part of a vessel – which can be closed and has two parts: The colder, upper part contains brine mixed with water vapor at low temperature and low pressure; the lower part is separated from this cavity by a metal slab with high thermal conductivity. The colder vapor is compressed; and the compressor is driven by a water wheel. To start the process, all cavities are filled with vapor heated to 100°C at the beginning.

At a higher pressure, the evaporation / condensation temperature is higher. Thus hot, dense vapor condenses on the top of the lower cavity, releasing heat which is available in the upper cavity to heat the colder ‘input vapor’. This makes salt precipitate in the upper chamber where it was collected regularly.

In a heat pump for room heating a refrigerant running in a closed cycle is compressed by a mechanical compressor powered by electrical energy. At low temperatures and low pressures the refrigerant evaporates easily, even when in contact with a cold heat source (such as our water / ice tank at 0°C in winter). After compression, vapor condenses at temperatures higher than room temperature and thus the refrigerant is able to release the heat ‘harvested’ before. Rittinger’s steam pump is called The First Heat Pump by historians: However, in this device the water vapor mixed with salt brine is both the ‘refrigerant’ and the liquid to be heated!

In his paper, Rittinger explained that you could as well start from a brine at a temperature as low as 10°C, not needing any auxiliary heating. The system would operate at lower temperatures and pressures. But due to the lower pressures the same material would occupy a larger volume and thus the system had to be much bigger. I suppose, taking into account investment costs, this would have been less economical than using a bit of fuel to get the process going.

What I found intriguing about Rittinger’s work – and perhaps about the way research publications were written back then – was the combination of hands-on engineering, theoretical modeling, and honest and ‘narrative’ reporting of difficulties. Zogg’s history of heat pump quotes quite a number of Leonardo-da-Vinci-style inventors with diverse interests and an obviously ‘holistic’ approach.

Martin Zogg notes that using today’s technology, such ‘steam pumps’ easily obtain a coefficient of performance of 15 – more than 3 times the COP of a heat pump used for room heating. Mechanical vapor compression is state-of-the art technology in salt processing. The reason for the high COP is the lower temperature difference between hot and cool brine vapor. You just need to provide for a sufficient temperature gradient to allow for heat transport from the hot to the cooler cavity, and to overcome the change in evaporation temperature (according to Raoult’s Law).

I could not find the figures in the original paper that Rittinger referred to. The following image is a link to a clickable, larger version of the figures Rittinger had added to a later paper dated 1857, on the actual results of his experiments. Its title was: Darstellung der zu Ebensee abgeführten Versuche über die Reproducirung der im Wasserdampf gebundenen Wärme durch Wasserkraft behufs ihrer Verwendung zum Abdampfen der Salzsoole.

At the time of writing this article, Rittinger’s 1857 paper was at In 2022 this link is (currently?) broken, connection to times out. This web page was provided by digitized archive of Polytechnisches Journal, by University of Berlin, and it also an ‘interactive map’ allowing for zooming in on parts of the construction.

In 2022, some of the images are still in the Google Cache. I also noticed that these images and the links have been shared on social media after I had published this blog post in 2015. I was able to salvage one higher resolution image to which this thumbnail links now (after the original link to broke).

Drawing of Peter von Rittinger’s steam pump, click to enlarge. Digitized by Polytechnisches Archiv, Berlin. Hosted on my site (temporarily?) as the original source is not available anymore.

What looks like a top view of spaceship Enterprise is the vessel seen from the top. On the left, the corresponding side view shows that it was rather tall. What had been described as a simple separating wall-style flat heat exchanger was actually built as a system of several cylindrical cavities (to increase the heat exchanger’s surface). In the figure the cavities containing high-pressure vapor are denoted with b/c/d. The steam pump / compressor is denoted with E, Dampf-Pumpe, and shown to the right of the vessel in the side view.

Though the numbers were in line with his theoretical calculations, Rittinger’s pilot system did not work well: This was an unreliable batch process, as the vessel was opened regularly to remove the precipitated salt. Rittinger made some suggestions in his original paper, on how to harvest salt continuously. From experience he knew that salt crystals should easily glide downwards from a tilted plane. But among other issues, Rittinger noted in his research report from 1857 that salt crystals behaved quite differently in his vessel, and he attributed it to the higher temperatures in the closed vessel: Instead of being able to harvest the loose crystal at the tip of the conical vessel, all vertical planes have been covered with a crust of salt that resisted also the strongest chisel.

His epigones finally solved such issues – quoting Zogg again:

Probably stimulated by the experiments of Rittinger at Ebensee, the first truly functioning vapour recompression salt plant was developed in Switzerland by Antoine-Paul Piccard the University of Lausanne and the engineer J.H. Weibel of the company Weibel-Briquet of  Geneva in 1876. In 1877, this first heat pump in Switzerland was installed at the salt works at Bex. It was on a larger scale than Rittinger’s apparatus and produced around 175 kg/h of salt in continuous operation.

This images shows a historical piston compressor, installed 1878 in the salt mine of Bex, Switzerland (Wikimedia, public domain, from Martin Zogg’s History of Heat Pumps). 1943 it was still in operation!

21 Comments Add yours

  1. Great Post. Would like to read more from you. Keep posting.

  2. You know I was actually graduated and out there teaching physics before I ‘Got’ heat pumps. I’d never considered thermo very much and, so, just stuck with the laws of thermodynamics thinking that the best we could do was 100%. Not even once did it occur to me that instead of generating heat we’d be better off in using our available energy in moving it from an existing source. That’s part of the reason I love humanity :-)

    1. elkement says:

      I feel thermodynamics is often underappreciated – compared to say, ‘exciting’ quantum mechanics. But it is so fascinating to explain the same thing using just simple ‘phenomenological’ equations or start from statistical mechanics. Perhaps it is the statistical nature and probability that sneaks in and makes it non-intuitive, even when trying to explain ‘simple’ concepts. I often mull upon the simplest possible way to explain why heat pumps work and why they are not crackpots’ ‘overunity’ magic. I always end up thinking about the fact that compared to absolute zero the temperature of heat source and building are not that different so it is rather easy (in terms of required input energy) to tap onto the potential of heat energy in the rather ‘cold’ source.

      1. Joseph Nebus says:

        Thermodynamics is definitely under appreciated. I suspect the trouble is that the mathematics which explain so much of its wonder was developed barely a generation before quantum mechanics came in and captured the public imagination for wondrous and almost magical physics. And so much of the mathematics for thermodynamics goes into quantum mechanics that even if one wanted to explain what’s neat about thermodynamics, it’s just as easy to explain for quantum mechanics, which people are already thrilled by.

        1. elkement says:

          Thanks, Joseph – yes, your explanation sounds absolutely plausible!

  3. I posted this in my (generally) neglected Google+ account, given that I have a lot of love for stories which both explore the winding path of innovation and the accidental arrivals at unplanned destinations. As I think I’ve mentioned before, I also wonder if there is still some knowledge to harvest from old technologies, as though the essential idea might still have something to offer in the contexts of new ideas and developments.

    Also, I love your opening lines: “Peter von Rittinger’s biography reads like a success story created by a Victorian novelist, and his invention was a text-book example of innovation triggered by scarcity.” This past year I read Jessica Lamb-Shapiro’s book, Promise Land, in which an early chapter examines that Victorian rise of the success narrative. I’ll share a bit:

    “More than individuals of any prior era, Victorians embraced the tenets of progress, discipline, and self-betterment. During the Industrial Revolution, people moved to cities in record numbers. As modern living became chaotic and baffling, Victorians searched for structure and order. Self-help provided this, as well as a way to organize and disseminate knowledge.”

    The book goes on, leaving the suggestion that the last scalable frontier any true tinker could explore was the inner landscape of the self. It seemed that as the possibilities for Renaissance men diminished with the vast growth of knowledge, we all became a little lost on the roads of specialization. No longer certain about what to do, we also lost a sense of who to be: humans entered an age of a collective identity-crises from which enterprising individuals found a solution and an income. Thus, arose the industry of self-help books as “a prescripted path to self-improvement.”

    1. elkement says:

      Great comment, thanks Michelle! Re old technology: Salt production today is still using thermo-compression, the principles are the same as the ones the pioneers used.
      I think my opening line was motivated by vague recollections of Dickens and my reading of all Sherlock Holmes stories some time ago. Now I am reading all novels by Agatha Christie and I think even in that later period it was very hard for a poor orphan in a society that was still so class-conscious in the 1940s. Perhaps it’s also ‘not correct’ to assign the term ‘Victorian’ to middle European culture. E.g. Vienna’s Fin de Siecle culture had some distinct features I believe (…Think: Freud, morbidity,…).

      Your comment on pioneers is interesting as this is a book I might read some day (it was quoted in my favorite book on early hackers of the phone system):
      The Victorian Internet: The Remarkable Story of the Telegraph and the Nineteenth Century’s On-line Pioneers.

      1. Maybe I misread the post, but I had the idea that this heat pump design came from the problem of trying to increase energy efficiency in the salt collecting process, and the heat pump itself held interesting possibilities for other things.

        Also, as I’ve been thinking about it, there a lot of interesting questions about how temperature variations and brines could differ to create differences of product.

        The British did have a flavour all their own, but upper class European culture was so interconnected (most of them related to one another) that without being specialized, I can’t quite find any wide distinctions (which there probably are) from one group to another. Sometimes they seem to be like one big, scrappy (insane) family.

        Class mobility is also an interesting topic, as some societies in the Western world have started the move back to those Victorian era restrictions again. Canadian newspapers have been carrying stories about how the restrictions on immigrant families (i.e. access to university-streamed education, better paying jobs) is one of the underlying causes of the process of jailing to radicalizing youth in France. In the U.S. there is more outcry about the “prison pipeline” as the education system either supports or fails children largely based on the race, ethnicity and education levels of their parents. (Even as the narrative of self-made successes is repeated over and over.) Of course, even with a relatively positive history of successful immigration, I can see that Canadians haven’t been completely free with one another, either, and have committed significant violations to indigenous cultures in particular.

        I’ll leave off there. I was going to write more, but it could end up being a mini-post inside your post. I am enjoying your history lessons, by the way.

        1. elkement says:

          You understood the post in the way I meant it, Michelle! In my comment I tried to refer to heat pump technology being an example of an old technology that had been exploited very well – both in relation to the field it had first been invented for (salt production) as well as other ‘modern’ ways of heating and cooling.
          I just wanted to make sure that my post is not understood as archaeology of ‘forgotten’ technology because I limited the scope of this post to the historical invention only, not mentioning all the later ideas and gradual development and extension to various fields (documented in this ‘History of Heat Pumps’ document… It is always a challenge to do justice to great, detailed work like that but still distilling part of that into a self-consistent and fairly short post.)

          I had an interesting discussion with a colleague who has lived for years both in Austria and the UK (and other countries): He told me that he feels the British society is still dominated by ‘classes’, much more than in middle Europe. [Disclaimer for readers from the UK: anecdotal evidence, I don’t want to prove anything…].
          On the other hand I recall when reading Christie’s novels and her references to servants and ‘those classes’ decades ago I did not notice it – now I cringe every time such a phrase comes up. So it is likely our society was also more class-based even recently. Our (German/Austrian) educational system definitely still is, with diverse schools and major decisions to be made when children are 10 and 14 years old … decisions which still (on average) depend on the non-existant classes and determine the future careers.

          1. This is a good post, and it does convey the subject’s complexity with efficient distillation ;).

            A conversation with one of my former professors yesterday has left me reflecting on some changes that have been occurring locally in post-secondary education as the divisions between college and university are blending, with more joint programs being offered to prospective students. On some levels, it is pure pandering to employers, as some programs now train quite specific skill sets based on corporate requests. On another level, it might result in a kind of hybrid worker, one with both technical and academic training. I can’t help but wonder what the impacts will be. Perhaps, more contract workers as pieces of production are split up and done by specialized labour? Or, greater social mobility, as young people are given a blend of skills to both get them in the door and to advance in a career. It seems a far step from other trends, such as splitting very young children into education groups and enforcing their limits with specific training opportunities. This sort of thing happens in the larger secondary schools, but as most communities that feed into the post-secondary system here are too small to divide such training, the advanced placement rarely offers advantages at university/college as a set of separate or special opportunities.

            1. elkement says:

              Very interesting – maybe somewhat similar to the way our systems morph: We had no distinction between ‘college’ and ‘university’ but only 5 years master’s programs at universities (all doing research, no teaching only). Then so-called University of Applied Sciences – Fachhochschulen, FHs – were founded in the 1990s – 4 years programs tailored to industry’s needs, focused on teaching sought-after employable skills, often combining technical and economical skills (thinks programs like Process Engineer). They resulted in a master’s degree with a suffix FH. The came the Bologna process in Europe and all degrees in traditional universities and FHs were split into bachelors (3Y) and masters (2Y), which means FH degrees were extended by one year. Overall results:
              – All kinds of schools and universities become more similar to each other and competing more with each other, everybody does ‘research’ (also including so-called technical and business high schools, which seem to be more similar to bachelor’s programs now).
              – Maybe watering down standards as they seem to be so many programs competing for the same students and you don’t want to scare anybody off. By ‘too much math’, for example (literal quote by a university executive).
              – Maybe redefining ‘research’ as every project requiring some structured approach and quality assurance is called research now, as every school has to do PR, twitter like hell, and market their ‘research’.
              – Education become more canned, more like ticking off separate little modules on a to-do list; many tiny exams instead of one large grand exam at the end.
              – More bureaucracy, admin personnel, quality management, and teachers, scientists, and students loathing it. Lots of jobs created in the public sector. Unfortunately a good training for the corporate world and inbox-/deadline-driven work.
              – Greater social mobility as FHs were built in rural areas on purpose, lowering the bar and travelling costs for students in ‘working-class’ families.

            2. From an earlier date, our local universities offered a lot of these things you’ve listed already, like the short degree to which you can add on graduate studies. I think this might be taking it one step further now. I am not sure what to make of it. In reality, I suspect that the entry-level tech training blended with a more liberal education to aid career advancement is a generation too late. This is what people my age had to do to compete in a labour-saturated work place, and the training to solve this problem is now just being put in place. For younger workers, like our children, the solution to their struggles probably won’t be offered until the next generation, and already needs will change. It is as always: we can see what has already happened, but can’t predict what has not yet come. Society will probably always be one life time behind in meeting its needs.

    2. Great comment on a really interesting post. I know there are new insights to be harvested from old art – Vermeer, Turner, Chardin, and Schwitters are useful for me. So it seems likely old technologies might contain new ideas. The previously irrelevant can be very important.

      But for something completely different, a book called Banvard’s Folly about ideas that were mostly wrong is a great read. It’s all grist for the mill.

      1. Interesting. Thanks for adding the reading suggestion.

  4. So, he invented the heat pump, and unwittingly also the vapor deposition technique :-)

    1. elkement says:

      Who knows what a large-scale hard crust of salt might be good for :-)

  5. howardat58 says:

    Fascinating. I need to read it again.

    1. elkement says:

      Thanks for reading, Howard!!

  6. Irgendeine says:

    In the Austrian anthem is: “You are home to great sons and daughters…..”

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