The lost warmth
When the energy crisis in 1973 snatched the prosperous West from its comfortable dream, most people started in frenzy taping windows and turning down heaters.
My family instead moved south to Curaçao, the tropical part of the kingdom of the Netherlands. As a five-year-old boy, I adapted quickly to my life on the island. On the north coast, plastic and driftwood washed ashore which I enthusiastically collected to build houses, cars and boats. Any piece of waste turned into valuable parts for my constructions. It kindled the inventor in me.
The island’s economy thrived on refining crude oil coming from Venezuela. While poisoning smoke from dozens of chimneys destroyed nature and cultural heritage downwind, oil consumption worldwide kept increasing. Within a few years, the energy crisis was forgotten.
And after a while in the tropics I was no longer able to imagine winter cold. The concept of snow only exposed itself as crystals on the inside of our freezer.
Seven years later, back in the Netherlands I had to wear shoes (!) and zip my warm jacket before running outside to play. I hated the hassle of dressing, and stayed mostly inside. It was only two decades later when I got a dog that forced me to go out despite rain, wind, or snow, that I started to appreciate the change of seasons.
Creating solutions in times of need
When I studied architecture, I lived with other students in a former office – a massive stone building that was one of the first cast concrete constructions in the Netherlands. As the original heating system had been removed, we placed second-hand Aladdin paraffin heaters under our drawing boards to keep warm.
It didn't work. During our first winter, we packed ourselves in layers of woolen sweaters and fingerless gloves (we still used technical ink pens on tracing paper). But cold crept into our bones and our brains. It blocked our common sense and affected our mood dramatically.
When spring arrived and it got warmer outside, the building stayed cold like a deep cave. In fact, the metal- framed, single-glazed windows fogged on the outside! It took months for the mass of concrete to release the cold.
Luckily, my creative mind was challenged, and I began to look for alternative solutions. The following winter, although we hardly had any money to invest, we started to improve the situation.
I thought of heated chairs and tables that would keep our bodies warm, even if the air around stayed cool. Wood stoves proved too hot to sit on, and also produced a lot of smoke and dust. So we decided to invest in a cleaner central heating system running on natural gas. Over a period of three months, we installed the whole system ourselves – again using second-hand parts to reduce costs. We connected flexible rubber tubes to old cast iron radiators and placed them on wheels to serve as rolling chairs.
The cost of operating the system was much higher than we expected.
Firstly, because the building was made of massive concrete, the walls and floors absorbed most of the produced heat – leaving the rooms and us still cold. Secondly, the water had to be heated to over 80°C (175°F) for the cast iron radiators to be effective. Heating water to near boiling temperature requires up to four times more energy than heating it to 30°C to 40°C (85°F to 105°F) – i.e. close to the body temperature that we needed. So, we started experimenting with lower temperature systems. But metal radiators as we know them from the central heating system in our homes are not at all effective at lower temperatures; at these lower temperatures, they tend to condensate and corrode.
What we did learn is that stone radiates heat better. So we casted plastic water tubes inside blocks of concrete instead, just like is done in under floor heating. With this approach, the stone surface became warm but not too hot. In fact, it gave a very nice warmth, just like the stones on the beach I knew from my childhood in the Caribbean. The idea of heated furniture was born.
Connecting to the basics
Once I finished school and was working as a professional architect, new challenges arose- and new crazy ideas followed. One project was to transform an industrial hall on an old ship wharf in Amsterdam into artist studios.
The artists had the same problem of being cold, so I introduced the idea of concrete furniture with cast-in tubes as the main source of heating. The new tenants, being artists and crafts people, made their own chairs and tables, and connected them to the low temperature water circuit that was built into the design.
In this case, we were able to reduce the energy needed by using water from a river nearby. Since only surface water reacts immediately to the air temperature above, water at deeper levels in the river stays warmer all year round. This means that even when the surface is frozen, deeper water temperature might be at 10°C (50°F). To heat that water to 40°C (105°F) requires only little energy input.
Surely, the idea was not totally new since under-floor heating and heated walls were already common practice. Even the Romans transported warm air through under floor ducts to heat the pools and benches of theirs baths. Today, pre-heating of water can also be achieved with solar collectors on a roof.
In a subsequent project to turn an old school into apartments, I again worked on the idea of stone heating. Together with partners, we co-developed a massive free-standing concrete Finnish style heater. ‘Fin-ovens’, as they are known, are much more efficient than traditional cast iron wood stoves or open fire places.
In contrast to slow-burning logs in wood-fired heaters, Fin-ovens burn 6 kg of chopped wood in less than an hour at extremely high temperatures (over 1 200°C [2 200°F]). Through a combination of techniques, this process reduces pollution to almost zero. First, the wood is stacked as a straight tower and lit from the top; this first burns the wood gasses that are released when the temperature rises. Inside the Fin-oven, a series of different chambers facilitate after-burning to combust all remaining gasses; this leaves almost nothing but water vapor and carbon-dioxide (CO2) exiting the chimney. In addition, the combustion reaches a rate of 80% efficiency, which is extremely high for a wood-fired heater.
Fin-ovens have other advantages as well. During combustion, heat is stored in the concrete mass; over the full cycle of a day, it is slowly released as infrared radiation to the surrounding room. Just like the sun, infrared becomes heat once it hits a surface – such as a wall or your skin. All stone mass in the room like walls and floors contribute to the radiation effect since they are heated up as well, and start radiating back. In case walls are not insulated, a good alternative solution is to insulate on the inside with mineral-wool insulation slabs with reflecting foil facing the room. Gypsum boards create a good finish to optimize the effect of radiation in the room. Ultimately, the effect is like the sun on a chilly spring day. Infrared radiation does not actually heat the air, but its heat energy is 'perceived' when it comes into contact with a person's body. Thus, the temperature a person 'feels' may be much higher than the actual room temperature.
This systems also has the benefit that natural ventilation, for example by opening windows for several minutes a few times a day, does not affect the overall temperature too much. Moreover, the surface of the heater never gets over 60°C (140°F), making it the perfect object to lean against.
To take this system beyond the converted school, I started a workshop where I would help people make their own forty-piece Fin-oven heater in two days - including the back-breaking work of casting the heavy concrete elements. For each part, we had molds to cast the concrete elements. I discovered that the act of making their own heat source makes people appreciate heat in a totally new way. Heating your own home becomes an conscious emotional act, just like enjoying good food. Lighting your own fire brings back an ancient feeling of connection that contrasts radically with the current disconnection that arises due to the automated thermostat most homes are equipped with.
From there, I continued my quest for affordable sustainable solutions while also exploring the connection of people with their surroundings. I found my way to comfortable warmth and I thought the circle with my childhood had closed.
Generating an 'inner fire'
Then I met the Iceman, a man focused on overcoming the cold instead of searching for warmth. Wim Hof from the Netherlands holds over 20 world records in cold challenges. He climbed Mount Everest and Mount Kilimanjaro in shorts, swam under the arctic ice and appeared on Japanese TV sitting in an ice-bath for two hours.
I became interested why, and more importantly how, does he do it? He is no freak of nature as I learned along the way. He actually enjoys the warmth of the sun just as much as I do. But he trained himself mentally and physically to turn up his own thermostat and to withstand the cold he calls 'a noble force'.
It took me only ten weeks to adopt his technique. It now has become a daily routine of breathing exercises and basic yoga combined with a cold shower or a swim in the sea. Both physically and mentally, I became stronger and more resilient through these exercises. Not only do I not fear the cold anymore, I actually got healthier and more resistant.
Many aspects of modern science at large aim to improve our standard of living. We make our homes ever more energy efficient, but strangely we are hardly reducing energy consumption. Rather, in well-insulated houses, people tend to turn up the thermostat and walk around in a t-shirt in winter.
I believe that with the speed of the transformation we have gone through in the past decades, we have lost some basic human skills. Our ancestors did not have access to the luxury of fully heated homes that we are now accustomed to. Instead, people in cold climates were more resilient. Since comfort solutions were not as readily available as now, most people naturally had a more practical mind-set and could withstand extreme temperatures more easily. They developed skills to make proper clothing for each climate and season. Whole families – and even strangers – snuggled up against each other's warm bodies to get through freezing cold nights.
It seems now that the more we get disconnected from the social group, the less resilient we become. Bluntly, I come to the conclusion that we have been drifting apart – heating our ever-growing 'personal bubble' while we are actually longing to be closer to friends and family, to receive and to be able to give more physical and mental warmth. But all we do is compensate with higher indoor temperatures and going on far-away sunny holidays to recharge.
Surely, the situation of 100 years ago was far from ideal. Life expectancy was lower than nowadays. But this is definitely not a matter of 'either or'. We need to move forward by learning from the past. When financial resources are limited, conventional solutions may not be the optimal choice. There are multiple ways to stay warm, but it requires people to take matters into their own hands. Scientists should not focus only on high-tech solutions, but also on finding affordable alternatives for people in need.
In Romania, I contribute to the NGO Arhipera, working together with local communities to help construct houses for the poorest families. Summers there are tropical while winters are polar. In contrast to the many opportunities I had as a child and later as a student, the young people in these villages lack the basic needs in life. Many families have no home at all, and children therefore do not get the chance to go to school. The houses we build with them are simple but provide a good shelter in the harsh climate. Having a place to live allows parents to focus on earning some money while the children can go to school and establish a place in society. The houses are just that small push needed for people to move away from poverty.
Having the basics right will help increase people's physical and mental health, and thus their ability to make the right choices. It all sounds almost too easy. And I realize for many people without money and perspective, it is a tough struggle to overcome. When people lose their loved ones, lose their jobs and suddenly are in the situation of fuel poverty, it takes a lot of motivation to find suitable and affordable ways to withstand the cold. I hope my ideas described here open possibilities when the common solutions are out of reach.
EnAct is grateful to Sebastiaan Veldhuisen, ROCKWOOL International for sharing his life story and life's work! .