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Podcast S17E005

In conversation with…. Luigi Tischer, Ariston


Using gas as efficiently as possible has come into even more focus in the current energy crisis. While electrification will continue to be the broad thrust of decarbonisation efforts, gas will have a role to play – particularly in some types of buildings – for many years to come. So it makes sense to use gas as efficiently as possible. In this episode, Jon Slowe talks with Luigi Tischer about thermally driven heat pumps – which can dramatically improve the efficiency of converting gas into heat.

Episode transcript

[00:00:04] – Jon Slowe

Welcome to Talking New Energy, a podcast from LCP Delta. The new energy experts. In the podcast, we'll be exploring how the energy transition is unfolding across Europe through conversations with guests from the leading edge of the transition.


[00:00:21] – Jon Slowe

Hello and welcome to the episode. Across Europe, we're still hugely reliant on natural gas for heating, and we're going to be reliant on natural gas for many years to come, even as electrification of heat gathers and accelerates pace. Now, I'm sure most people listening are familiar with heat pumps and can probably describe at a high level how they work. Today, we're looking at a type of heat pump that I think many of you won't have heard of, one that's powered by gas or heat and can use gas way more efficiently than a condensing gas boiler. And while electrification is and will be the main focus for decarbonising heat, dramatically increasing the efficiency in which we use gas will be a really important stepping stone or even potentially an alternative route to decarbonisation with green gases. And today this is particularly important as in the energy crisis, we try to reduce consumption of the natural gas in Europe and reduce our reliance on manage to be not reliant on rushing gas. Now, to introduce this topic and discuss a bit more about thermally driven heat pumps as they're known, I have a special guest, Luigi Tischer. Hello, Luigi.


[00:01:49] – Luigi Tischer

Hello, John. Thank you for inviting me.


[00:01:51] – Jon Slowe

Thanks for joining, Luigi. Well, I think I should introduce it as one of the parents of thermally driven heat pumps, people in the sector will know, Luigi has been involved in this area for many, many years and now leads this area with Ariston, an Italian company, one of Europe's top five heating appliance manufacturers. So, Luigi, well, has it been your life's work? Is that too much, or it's been many, many years of work?


[00:02:27] – Luigi Tischer

Yes, quite a while. Almost two decades dedicated to the development of this technology and the market and creating norms and regulation compatible with the development of this market.


[00:02:42] – Jon Slowe

Okay. And to help our listeners understand, let's just look a bit about what thermally driven heat pumps are before that. Where? In Europe. If I'm a homeowner, a household, are there countries in which I could buy a thermally driven heat pump today?


[00:03:02] – Luigi Tischer

So, thermally driven heat pumps are available in many European countries today, and more countries will soon be offered this product and this technology, thanks to the introduction of new players, in particular the one we are representing, which is Ariston.


[00:03:29] – Jon Slowe

Okay. So, it's all have a complete coverage of Europe very soon. Okay, so it's very much on the market, even if it's not yet particularly widespread.


[00:03:39] – Luigi Tischer

You're correct.


[00:03:41] – Jon Slowe

So, let's help our listeners understand what a thermally driven heat pump is. So, it's a challenge to do this without getting too technical, but that's your challenge, Luigi. How can you explain it for someone who might be working in the electric vehicle? Charging space and isn't a heat expert at all.


[00:04:00] - Luigi Tischer

So, let me say first point is correct is a heat pump. So, it delivers heat at a higher temperature from where the heat is taken. So, we take heat from the environment very frequently air, cold air in the winter we subtract heat to the environment, and we move it at higher temperature level where we, let me say deliver this to the end user, usually radiators or in any case an emission system for the building. So, this is what a heat pump does. The way in which we do is substantially different in two ways, internally to the equipment. We don't have a mechanical compressor like an electrical heat pump, but we enjoy a thermochemical process which increase the pressure of the refrigerant which is circulating within the heat pump. On the other side, this process is activated by I, would like to call it molecular energy vector or natural gas. But why? I'm generalising because in the future might not be only natural gas. It might be natural gas plus something else biometric or might be only bio-LPG or blended with hydrogen. In other words, we will see as in parallel to the decarbonisation of the electrical vector we already see movements in the direction of the decarbonisation of what is today the gas sector.


[00:05:45] – Jon Slowe

Okay, so to summarise what you said so far, there's an outdoor unit that absorbs heat from the outside air. It will deliver heat to radiators and then that cycle is effectively driven by a thermochemical processor that's driven, simply speaking, by combustion of natural gas. That could be combustion of a different gas.


[00:06:10] – Luigi Tischer



[00:06:20] – Jon Slowe

I like to think of what many listeners may know is that you can get a gas-powered fridge and while most fridges are electrically powered, they can be powered by heat. And in a way that's a nice parallel for a thermally driven heat pump.


[00:06:28] – Luigi Tischer

It's a little bit more than a parallel because the two technologies are very close to each other. Those refrigerators which are used in the minibars of the hotel when the hotel minibar is very quiet and silent very often is an absorption refrigeration system as well as refrigeration system in yachts or caravans are based on absorption processes. The basic physical fundamental process is very similar, almost identical. Where the difference is we consider the user for net effect the heating in heat in those appliances. What you look for is cooling. But it's the same process.


[00:07:19] – Jon Slowe

Now for electrically driven heat pumps, depending on how they're set up and used, you might have one unit of electricity in let's say three units of heat out. For a thermally driven heat pump you might have one unit of natural gas in how many units of heat out?


[00:07:41] – Luigi Tischer

Usually depending on the different technologies because within thermally driven heat pump we have different possible families. But usually, we talk about 1.5 - 1.6. as performance then is in particular on radiator, we can maintain a performance of 1.5 - 1.6 on 55 or 65 Celsius.


[00:08:06] – Jon Slowe

Yeah. Okay, so a gas boiler, a condensed gas boiler may be between 80 - 90% efficient.


[00:08:15] – Jon Slowe

Yes. A thermally driven heat pump is about 150 - 160% efficient. Yeah. So, the thing that I find really fascinating, Luigi, even if a lot of heat we're going to electrify, we're going to be using natural gas for a long time, some buildings will be difficult to electrify. And if we can go from 80% - 90% efficient to 150% -160% efficient, we're almost halving our use of natural gas for heating, which seems like a no brainer.


[00:08:53] – Luigi Tischer

Yes. In addition, I would say this can be done immediately. In other words, it doesn't rely on expectation. And let me say additional step needed, like the decarbonisation of electricity, like the addition of seasonal storage capacity on the grid, whatsoever. The infrastructure which is in place today on the gas grid will allow immediately to recover this 40 plus percent of savings on the consumption of our current building. In particular, in those buildings, which are the majority existing building of poor quality in terms of insulation for a tonne of different reasons. It might be architectural constraints and might be other limits, but in those buildings, very often in categories FG and E, it's not easy to upgrade or improve the quality of these buildings and the solution fit very well because of the fundamental principle on which the technology works. While it's not achieving very high level of efficiencies, on when the thermal lift or the climatic condition are favourable, is not decreasing almost at all when the thermal lift is critical.


[00:10:23] – Jon Slowe

Okay, so when you're, when it's really cold outside and you still want your radiators at 50 or 60 degrees, 65 degrees, the performance of the heat pump doesn't drop off, it stays fairly constant.


[00:10:37] – Luigi Tischer

And let me say it's not only a matter of supplying high temperature, which is extremely important if you have radiators and, and if it's cold outside, you need to reach those temperature 55, 60, 65, 70. Yeah. But it's also the ability in those conditions to deliver power. So constant power is one of the features that the latest thermal agreement are capable of delivering across the entire working envelope. This makes a very unique technology in the scenario.


[00:11:13] – Jon Slowe

Okay, so I don't want to get too much into the argument for whether you electrify heat or use gas and decarbonised gas can get very polarised. I find that time, I think it's clear that there are some homes where it's going to be very hard to electrify heat, and in those homes, a thermally driven heat pump, the outdoor unit you still need. But some other things are simpler. Now Ariston, the company you work for, tell me a bit about Ariston, your strategy for decarbonisation and how a gas driven heat pump or thermality driven heat pump fits into that. Ariston, placing bets or is it a portfolio place to them?


[00:12:08] - Luigi Tischer

So, in Ariston we have, let me say, a mission which is providing sustainable solution for all our possible customer. And we do realise that Ariston has a very large geographical coverage from Far East to America's, Africa and Europe. But even only concentrating in Europe, the requirements of the European markets are very different. And we want to offer to all possible customer the best possible technology that fit their requirement and needs. And for this reason, we have, and we are growing a substantial range of condensing boiler, even hydrogen boiler. We have a range of electrical heat pumps which are currently succeeding in growing in the very respective market. We had hybrid solution combining condensing boiler and electrical heat pump. So, we still believe there are areas which are not completely covered in the heating or can be better covered with a specific offer which will increase further the efficiency of the previous system in certain application. We do not believe that there is one technology that fit all the possible application, but we need to have a different point in time for all the different markets, several technologies as demanded by the market.


[00:13:52] – Jon Slowe

Okay, so very much a portfolio approach offering a whole range of solutions for different building types, different customers, different markets.


[00:14:01] – Luigi Tischer

Yes, the company has substantially invested over the last few years in parallel on both electrical heat pumps  let's say, compression heat pumps and gas resources heat pumps, not in competition, but between the two, but in offering complementary service for markets that very often are not overlapped between the two.


[00:14:25.350] – Jon Slowe

Now, in terms of sales, thermally driven heat pumps are probably fair to say, orders of magnitude below electrically heated electric heat driven heat pumps today. How long have they been on the market and what's in your view, the biggest challenge? And it might be an internal thing within Ariston, it might be an external thing within policy environment. What's the biggest challenge to growing the sales of thermal driven heat pumps?


[00:15:05] – Luigi Tischer

Okay, they have been on the market for something like ten plus or 15 years so far. The real point is they were present in the like commercial market so that prevented achieving large volumes and large recognition. Entering the residential market is something that the technology has not yet attempt to do in general. So, when you approach the residential market that you start getting much more popular in terms of recognised by the policymaker, recognised by the installer and the planners and the end customers. So is clearly the big numbers generate out of the residential market. And this is fundamentally the reason why we at Ariston looking at this market even because it's kind of the market at this point in time and more interesting for Artiston in general is where our bread and butter.


[00:16:17] – Jon Slowe

And in terms of biggest challenge, I think there are lots of challenges is raising awareness from customers, so getting some pull for the product getting installed as enthused and excited about the product from a policy perspective, making sure that there are balanced incentives and support mechanisms that cover the technology. What's the biggest challenge of those? Might be one that I said might be one that I haven't said, do you think?


[00:16:54] – Luigi Tischer

I believe the largest will be awareness, because so far, we have managed to get the technology recognised at regulation level. For instance, the most important regulation on the HVAC sector, ERP 1.0, and even the new one, which is being drafted just now, ERP 2.0 do recognise thermodynamic pumps with specific category and specific mention and so on. So that is, let me say, achieved as well as the majority of European countries have subsidy scheme and legislation that allow on one side an incentive, on the other side the installation. The real problem is the lack of, let me say, residential products has limited the familiarity and the awareness of this technology in the installer and planner level and at the customer level. So, what we need to tackle now is this kind of awareness obstacle.


[00:18:11] – Jon Slowe

So, you now have the products. What's the role of a company like Aristotle in driving that? Is that Ariston's job? Is it other people's job? Or what are you doing to try and change that?


[00:18:29] – Luigi Tischer

Very difficult question in ten years’ time, when we have achieved it and we will be able to tell you what was the secret ingredient to get? But let me say there is a lot of things that we need to do in the different market with different priorities and different, let me say, instrument or tools. In my personal experience, there is not one single, let me say, strategy that works, because we have countries which have different tariffs, countries with energy tariffs, counties which might have different subsidy level, countries might have different legislation for the installation. So, Europe is a single market, but with a lot of peculiarities, in particular for the HVAC world. So, we need to understand, country by country, how to deploy the technology. Not easy and challenge, even for a larger group like Ariston.


[00:19:40] – Jon Slowe

Yes. And I think what I've seen from the heating industry a lot in the past and I'm generalising here is developing a new technology, maybe working with installers very closely, but dropping the technology in the market and then relying on the installers to talk about it, to push it, relying on others to get that customer pull. Because many heating appliance manufacturers have been quite removed from the household with the final customer. So, is that where Ariston can play the most in working with installers? Or do you believe a company like Ariston would ever help to create pulls directly from households and final customers?


[00:20:35] – Luigi Tischer

So, complex answer and I don't believe I know every possible solution. But let me say there are different stakeholders in the value chain and each of them might gain something starting from utilities, which might in this technology, a way to bring renewable energy inside the buildings through the energy, the molecular vector or the gas, through the gas network. And this is one. So, utilities might see an advantage and might be interested in promoting the technology and support technology. But even the installers might see, for instance, the advantage of having an easy installation in terms of certification and requirements. Let me simplify a little bit, but the concept is, if you are able to install a walling boiler with relatively limited training, you are in position to install a gas station heat pump or a thermally driven heat pump.


[00:21:46] ] – Jon Slowe

You basically need the gas qualification and nothing else.


[00:21:50] ] – Luigi Tischer

That is the bottom line. Then I would have some training experience, but maybe having installed few of them will make you a professional, let me say. But that is the point. So, installers might see this as a way to participate in the energy transition with their current skills and certification and, let me say, structure and organisations. But even planners might see a way to offer product that can address the problem of the current and future legislation where an amount of renewable is imposed or certain increase in energy efficiency of the building is either recommended or imposed or subsidised. This technology can really enter in that market and provide a solution to the planners. End users obviously will have a strong, let me say, drive in what in the operating cost, substantially reduced quietness of the appliance because it's clearly not having the compressor, not having a large ventilation system is clearly at advantages compared to alternative solutions. So, there are benefits for almost all the players in the value chain.


[00:23:18] – Jon Slowe

So, I think what you're saying, Luigi, is it will actually need the whole value chain to exactly work together. That for me is one of the critical challenges because there's no one overseeing or orchestrating the value chain and it's not easy whether it's an electric or thermally driven heat pump or any new heating technology. I think we've seen across Europe over the years how hard it is to introduce new heating technologies in big numbers into the market.


[00:23:54] ] – Luigi Tischer

Correct. We are very well aware of this and we also very likely are going to use different strategies through different organisation. You need to recognise that Ariston has a different way to reach the customer organisation that work on the long channel, organisation that work on the short channel. We interact with the installer easily with our certain brands and we go through distributors, but in any case, we activate the communication to installers and end users with other brands. So, we have different approach with the different brands, even if we are going to offer substantially the same fundamental physics and the same fundamental thermodynamics. But there are different products for the different brands that are part of our group.


[00:24:56] – Jon Slowe

Yeah. So, the work of the technology, the product and manufacturing, that's only half the work. Now, the communication side, as you said, the short communication, the long communication to households.


[00:25:11] – Luigi Tischer

You do not suspect a step function in which all of a sudden in six months we see volume growing. That is not expectation, but we believe we needed to work on a kind of medium to long term plan to get these, let me say, positive feedback on the technology and achieve these business objectives that we have in mind.


[00:25:39] – Jon Slowe

Luigi, looking back as one of the parents of thermodynamic driven and heat pumps, as I characterise you, you've been working on this in this area for 20 years. You said, if you look back, what do you think your biggest, personally, your biggest achievement is? Or when you look back at the challenges you've overcome, which challenge do you take particular satisfaction from having overcome?


[00:26:09] – Luigi Tischer

Wow. Difficult. Let me say I have been working with organisations that have supported the technology. I have been very often the front men, but it would be inappropriate to, let me say, concentrate on myself, the work or achievements. Let me say that in general, even as associations, because you need to consider that at this point in time, EHI (European Heating Industries) and EHPA (European Heat Pump Association) jointly support the introduction of the technology European market. And having achieved that, both side of the equation and the most important association in Europe are commonly sharing a vision for this technology and supporting the technology at European Commission level, I believe, something which is a little bit of achievement, not of myself, but all the players that have in many years that very often has happened, that I've been the frontman who was honoured by this and pleased, but this is one of the achievement. Another thing is getting recognised the technology and the majority of the subsidy schemes in Europe.


[00:27:38] – Jon Slowe

It doesn't automatically fit. Most people don't know about it. People jump to electric, it's renewable. Part of the heat it produces is renewable because it's using the air heat in the ambient air, but it still uses natural gas. So, yeah, it's not a straightforward one for people to get their heads around all the time, I think.


[00:28:03] – Luigi Tischer

Yeah. Sometimes it's difficult for people to understand that we can extract more heat from the primary energy, the natural gas of what is delivered possible simply because we use second principle, thermodynamics. And we extract heat from the environment, but it's not immediate. And most of the people tend to have a kind of surprise reaction when they hear that we can exceed 100% in heating.


[00:28:31] – Jon Slowe

But I think in the world we live in today, to be able to reduce our consumption of gas by that 100 and 5160 percent efficiency and that the retrofit, I wouldn't say is easy because you need an outdoor unit still, which is a change from a boiler, but it's a smaller step for the retrofit. So, yeah, I think it's a technology we need to accelerate as quick as we can. Which leads me, Luigi, to the crystal ball. So, I think let's bring out the talking new energy crystal ball. And from where we are today, if you look forward, I'll set the crystal ball to 2030. Where are we in 2030? If we fast forward to 2030, give me a picture of one aspect of thermally driven heat pumps in 2030. And that might be numbers of sales. It might be familiarity; it could be anything. But give me a picture for 2030.


[00:29:43] – Luigi Tischer

So, having said that, making forecast of the future is difficult, I would prefer to make forecast about the past.


It can only go so in reality, we need to consider that not always we are in position to predict all the, let me say, external events that can happen very likely. Nobody could anticipate the pandemic, nobody could anticipate the energy crisis, declining crisis and so on. I personally do not know what is going to affect us from now to 2030, but I believe that statistically something will happen and that it was not forecasted. Having said this and having therefore excuse myself for not giving exact numbers, because it's going to be extremely difficult, I believe that in this high level of uncertainty, we already have certain certainty. We know that the level, the amount of buildings in 2050, more or less 70% - 80% of those buildings are already here today. We know that those buildings will be even for the plans of European Commission, if I remember by heart, something like 60% of the building will be directly electrified by 2050. But the remaining portion what is going to happen? Can we take care differently? Can we improve the situation? Are we going to leave this to let me say to their own so I believe that offering this technology will accelerate in the market the adoption of urgent improvement to the bulk of the buildings.


[00:31:48] – Luigi Tischer

It's not wrong to improve further the efficiency of new buildings. It is absolutely right, no question. The point is we build limited new buildings and are already extremely efficient compared to the current status of the existing building. So, I believe that if we continue and try to accelerate the adoption of measures for the reduction of emissions will definitely be needed in new technologies, in this environment, and in particular, the approaching to this large issue, which is the existing building where we need the most. And there is where I believe the thermal driven pump will find a very unique, but not in niche, a relatively large opportunity.


[00:32:50] – Jon Slowe

So, Luigi, if we're doing this podcast again in 2030, hopefully we won't have to explain the basics of what a thermally driven heat pump is. Hopefully our listeners will know, and quite a few of our listeners may even have one in their homes.


[00:33:05] – Luigi Tischer

Yes, definitely.


[00:33:08] – Jon Slowe

Well, it's been great to have you on the podcast, Luigi, and hear your experiences and the opportunity to dramatically increase the efficiency of how we use gas for heating in our homes.


[00:33:25] – Luigi Tischer

And I would say even in the future, knowing that we are going to have a limited amount of green gases for those limited amount, we need to maximise the efficiency at which we will be using these gases. It can be hydrogen, can be bio, methane, bio-energy. We need to be smarter than just burning it.


[00:33:51] – Jon Slowe

We need to pay as much attention to the demand side as the supply side. I agree.


[00:33:58] – Luigi Tischer



[00:33:51] – Jon Slowe

Okay, Luigi. Well, as I said, thanks so much for your time. Thanks for joining us today. And as always, thanks to everyone listening, we hope that you learnt something new about heating. I'm sure there are lots of links if you Google gas driven or thermally driven heat pumps if you're curious to find out more. And you can even look at the LCP Delta website to see more of our research on efficient use of gas for heating. So, thanks to everyone and look forward to welcoming you back to the next episode next week. Thanks, and goodbye.


[00:34:35] - Luigi Tischer

Thank you. Bye bye.


[00:34:41] – Jon Slowe

If you enjoyed the podcast, then please rate it and share it with your friends and colleagues. If you're as passionate about the energy transition as we are, then you can keep in touch with us and look at our research, insights, podcast transcripts and download reports all at

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