School of Chemical Engineering

VIS (Vacuum Insulation System) - An Aalto University commercialization project funded by Business Finland

VIS (Vacuum Insulation System) is a new technology based on the idea of creating a vacuum inside a wooden construction element with the goal of achieving superinsulation and a long life cycle while using inexpensive materials. By lowering the pressure inside the element, we are able to utilize a technique called “vacuum drying” which ensures that the element will stay dry and healthy even in warm and moist conditions. These properties make VIS a perfect construction solution for demanding environments, such as indoor farming, where many insulation materials struggle. The goal of this project is to create the most energy and cost efficient indoor farming solution in the world called VIS Plant Factory.
Kuvassa keksijä Pasi Herranen VIS-elementin vieressä. Elementti on suuri, kiiltävän musta suunnikas.
Proud inventor and the element

Aalto Innovation Services has published an article about our projects

Finnish Glasshouse Growers’ Association grants VIS team a 5000 € innovation award


What is VIS?

VIS (Vacuum Insulation System) is a completely new technology that makes it possible to build energy efficient, sustainable long-life-cycle construction elements that perform well in humid environments both in cold and warm climate. The main idea behind VIS-technology is to form a vacuum inside a wooden element. This lowers the thermal conductivity of the element and helps keep the element constantly dry and healthy. The optimal pressure is maintained by coating the element with a barrier layer and by connecting it to a vacuum pump. When told so by the sensors inside the element, the vacuum pump removes the moisture and therefore mold cannot appear in the element. VIS elements are also designed to be VOC-free. The vacuum pump removes all VOC-emissions from inside the element and the outer surfaces are coated with VOC-free materials.

Vacuum drying

According to the water pressure saturation curve, the lower the pressure the lower the temperature at which water saturates. At normal pressure (1000 mbar), water saturates at 100 Celsius, but for example at 23 mbar, at 20 Celsius. When the water pressure saturation point is reached inside the element, water transforms into vapor that is easy to remove with a vacuum pump. The elements are equipped with moisture sensors that will start the vacuum pumps when needed. This technique is called vacuum drying and it ensures that the elements stay constantly dry and healthy.




The story of VIS begun in 2013 when Pasi Herranen, the leader of the project, had the idea of lowering the pressure inside a construction element close to zero mbars with the goal of achieving an extremely efficient thermal insulation solution that would at the same time be mold free. The development of this technology greatly benefitted from Pasi’s master thesis that focused on the strength of plywood that would become the main material of the element.

The early days of the project

While developing his idea, Pasi soon realized that by optimizing the inside geometry of plywood elements, it would be possible to build large-scale construction elements that would be strong enough to withstand a pressure close to zero millibars. Pasi graduated from Aalto University in 2014 and continued developing the VIS technology on his own accord. Pasi’s old contacts at Aalto University kept helping him with improving the technology and building the first VIS element prototype.

Forming of the VIS team

In fall of 2017, Pasi felt like the technology had advanced enough to start focusing on the commercialization side of the project. Luckily Pasi knew well a couple of economists, Orvokki Ihalainen and Panu Miettinen and asked them if they would like to take part in the commercialization efforts. Orvokki and Panu said yes right away and joined Pasi’s project to create team VIS. The commercialization process begun and the team spent the next few months exploring different commercialization paths. The aim was to find the field that most needed an energy efficient construction solution that survives well even in harsh conditions.

Greenhouses – a lot of room for improvement

The team quickly set its eyes towards indoor farming, where currently heat losses are significant and the environment is both humid and warm. In the past years, LED technology had advanced rapidly raising the value of better insulation. This is because artificial lightning has a double role in greenhouse cultivation acting as both a source of light and a heating medium. As the artificial lightning systems become more energy efficient, less heat is being produced in the greenhouses meaning extra heating is needed unless thermal insulation is improved. The improvement of LED technology also meant that indoor farming without sunlight in stabile and optimized conditions, such as in a plant factory, was becoming more and more cost-effective.

VIS Plant Factory

These factors inspired team VIS to start planning a solution based on the Plant Factory model already in use in countries such as Japan, USA and China. VIS team’s vision started to clarify: to provide the markets with the most cost and energy efficient indoor farming solution called VIS Plant Factory.

Greener food production is a global priority

Growing urban and declining rural population, global warming and scarcity of clean water are making it harder and harder to keep feeding the world. The most important way to ensure global food security in long term is to improve the efficiency of food production by improving the use of resources and labor in agriculture. Energy and cost efficient indoor farming solutions could help bring the production closer to labor and consumers, drastically cutting logistical costs of the whole industry.

VIS finds home at Aalto University

In the spring of 2018, the project become officially an Aalto University effort when assistant Professor Lauri Rautkari from Aalto’s department of bioproducts and biotechnology recommended that VIS would join Aalto University and apply for a commercialization fund called TUTLI. TUTLI is a Business Finland financing program aimed at researchers who are striving to make a business out of their research. The team spent the whole spring and summer honing the TUTLI application and this process turned out to be very fruitful: going over everything learned so far and distilling it to the form of an application helped bring structure to the whole project. The application was submitted in September and the team soon learned that Business Finland decided to fund the project and from the start of 2019 VIS Project has been operating of the premises of Aalto School of Chemical Engineering in Otaniemi.


Glass greenhouses – still at the mercy of weather

Maximizing of plant growth requires the levels of temperature, carbon dioxide and light being optimized continuously. Optimal conditions are very hard to maintain year-round in the poorly insulated glass greenhouses, because the varying weather outside affects the greenhouse climate making it unstable. For example, during warmer months, too high of a temperature becomes a problem. Rising temperatures inside the greenhouses force the farmers to open up the roof panels to bring down the temperatures. This makes it impossible to keep up the carbon dioxide levels at optimum and this is detrimental to the growth of the plants. In cucumber farming, for example, the size of the crops in the summer are only half of the size of winter crops.

What is a Plant Factory?

Plant Factory with artificial lightning (PFAL).

  • Completely closed system for indoor farming without sunlight

  • Utilization of energy-efficient LED technology

  • Possibility to optimize the growing conditions: 1) good thermal insulation leads to balanced level of temperature 2) minimization of air exchange to keep the carbon dioxide levels at optimum

  • Vertical growing: multiple layers of plants stacked on top of each other

  • Effective use of resources (for example water and carbon dioxide)

  • Profitability of Plant Factories is continuously improving with the technological development of LED technology

  • Plant Factories today are often built out of unecological and expensive materials like concrete and steel

  • Plant Factories are already in use in Japan, China and USA

VIS Plant Factory provides extra heat

Thanks to its insulation capabilities, no excess heat besides the one produced by artificial lightning is needed in the VIS Plant Factory. As a matter of fact, VIS Plant Factory produces excess heat even on the coldest winter days. This excess heat can be utilized in the heating of nearby buildings or glass greenhouses. During the project, the VIS team will also explore the possibility of connecting VIS Plant Factories to the heating district system.

VIS Technology in Plant Factories

The conditions inside a greenhouse are challenging for insulation materials: the relative humidity inside the growth space can rise to over 80 % and at the same time, the temperature difference between the inside and outside air can be over 50 Celsius. Thanks to the vacuum drying technique, VIS thrives even in these conditions meaning more focus can be put on designing the elements to be maximally cost effective, ecological and easy to manufacture. The VIS elements are also designed to have a long life cycle and minimal maintenance. Thanks to its modularity, VIS elements are easy to transport to and assemble at the construction site and VIS Plant Factors can be easily expanded later on.

Energy efficiency and more crop with VIS Plant Factory

As stated before, In the VIS Plant Factory, no extra heating is needed besides the heat produced by the artificial lights. This means that considerable amounts of energy is saved compared to traditional glass greenhouses even when taking into account the energy used by the artificial lightning. In addition to saving energy, VIS Plant Factory also increases the amount of crop. This is based on the fact that the most critical factors for plant growth, such as light, temperature and carbon dioxide, are optimal year-round.

Stability and predictability

Extreme weather phenomena cause problems in glass greenhouses and bring unpredictability to the cultivation business. For example In the summer of 2018 in Finland, a long period of heat caused partially destroyed crops in glass greenhouses. In the VIS Plant Factory such hardships can be avoided thanks to the closed system and superior insulation solution and the consistency that comes with it greatly improves the stability and thus the predictability of the business.

Solar panels at the rooftop

Even though VIS Plant Factory does not directly utilize sunlight, the advancement of solar panel technology has made it profitable to take advantage of the sun. A significant amount of  summers’ energy need can be produced with solar energy by installing solar panels to the roof of the plant factory and by directly using the electricity provided by the panels to power up the LEDs.

Vertical Farming

Vertical farming is a cultivation technique where multiple tiers of cultures are stacked on top of each other inside the plant factory. For example in Japanese plant factories, up to 15 tiers of lettuce are grown vertically, greatly enhancing the efficacy of land usage. When considering that each tier in a plant factory produces more crop than a similar-sized area in greenhouses or outdoors, a 15 tier Plant Factory efficacy per square meter is tens of times higher than in a greenhouse and over 100 times higher than in open field cultivation. More efficient land use makes it possible to bring the food production closer to cities where most of the consumers and workforce live in order to cut down logistical cost. More efficient land usage also means that parts of the land area currently occupied by fields can be turned into forests to help capture carbon dioxide and battle the climate change.

VIS Element in thermal energy storages

Efficient seasonal thermal energy solutions (STES) help energy supply and demand meet. As the production of solar and wind energy grows quickly, the volatility of the energy production rises and leads to situations when oversupply occurs. When this happens, the price of electricity plummets and some of the produced energy is dumped. During these moments of over-supply, electricity can be transformed into heat energy and stored into large water tanks. Well-insulated STES’s have minimal thermal losses meaning that the energy can be conserved in storage until there is a strong demand for heating. The energy stored in the hot water tanks is then distributed to the consumers using the district heating system. The current thermal energy storage solutions rely on expensive materials and have problems with scalability.  Thanks to its durability, cost effectiveness and scalability, VIS technology could be utilized in large scale, energy and cost efficient STES solutions.

Kuva Aalto-yliopiston punatiilisestä amphiteatterista
VIS has found a home at Aalto University


  • Project of the School of Chemical Engineering in Aalto

  • Duration 1.1.2019 - 31.8. 2020

  • Funding: Business Finland and Aalto University

  • Two main points of focus of the project: improvement and commercialization of the VIS technology

Case Japan, neuroverkon ja robotiikan yhdistäminen resurssitehokkuuden parantamiseksi

Japani on Plant Factory-kasvatuksen johtava maa, jossa toimii useita satoja suljetun ympäristön vertikaaliviljelylaitoksia. Japanin Plant Factorien resurssien käytön tehokkuus on parantunut viime vuosien aikana huomattavasti muun muassa LED-teknologian kehityksen ansiosta ja suurimmissa salaatti-plant factoreissa kerätään kymmeniä tuhansia salaatinpäitä vuorokaudessa. Alan kehitys on kuitenkin vasta alkuvaiheessa ja tekoäly- sekä robotiikkasovellusten odotetaan nostavan suljetun tilan viljelyn tehokkuuden uudelle tasolle. Tässä kohtaa jokainen lukija miettii varmasti tahoillaan, että jokaisen alan edustajat lupaavat tekoälyn ja robotiikan parantavan tuottavuutta moninkertaisesti lähitulevaisuudessa, joten seuraavaksi esittelen konkreettisen esimerkin siitä, miten näitä uusia teknologioita voidaan hyödyntää plant factoreissa.

Jokainen kasvi on oma yksilönsä omine geneettisine erityispiirteineen. Osa kasveista kasvaa todennäköisesti valioyksilöiksi, jotka viedään käsistä kaupan vihanneshyllyllä, kun taas osa jää alimittaisiksi rääpäleiksi, jotka päätyvät roskiin. Ongelmana on se, että mitä myöhemmin kasviyksilön ongelmat havaitaan, sitä enemmän on ehditty heitetty hukkaan resursseja, muun muassa keinovalotuksen vaatimaa sähköä ja lannoitteita, kasviin joka ei koskaan päädy kuluttajan lautaselle. Kääntäen siis mitä aikaisemmin voidaan havaita salaatintaimen huono laatu, sitä vähemmän tuotetaan hävikkiä ja sitä enemmän saadaan myytävää tuotetta per kasvatusneliö sekä resurssiyksikkö. Plant factoryn perimmäinen tarkoitus on muuntaa mahdollisimman tehokkaasti käytetyt resurssit lautaselle päätyviksi tuotteiksi, joten kysymys kuuluu: miten saadaan mahdollisimman tehokkaasti ja mahdollisimman pian poimittua huonot yksilöt pois kasvatuspöydältä tuhlaamasta resursseja? Tässä kohtaa avuksi tulevat niin kasvitiede, neuroverkot kuin robotiikka.

Robootti hoitaa kasvitutkijan työt

Kasvitietelijöiden parissa on jo pitkään tiedetty, että tietyn kasvin kasvupotentiaalia voidaan arvioida varsin tehokkaasti mittaamalla sen klorofyllin fluoresenssia. Lyhyesti selitettynä klorofyllin fluoresenssia mittaamalla voidaan arvioida muun muassa kasvin fotosynteesikapasiteettia sekä stressitilaa. Menetelmän hyvä puoli on se, että kyseinen mittaus voidaan suorittaa häiritsemättä kasvin elämää pelkän sinisen valon LED-pulssin ja kameran avulla.

Moriyuki ja Fukuda (2016) kehittivät tähän menetelmään liittyen täysin automatisoidun prosessin, joka pystyy erottelemaan kuuden päivän ikäiset salaatintaimet menestyjiin ja vätyksiin. Kuuden päivän iässä salaatintaimet ovat vielä hyvin pieniä ja tämän vuoksi niiden analysointi on nopeaa, sillä yhdellä 60cm*60cm tarjottimella kasvaa jopa 600 salaatintaimea ja robotin avulla voidaan näin valokuvata 7200 taimea päivässä. Kun kasvit saavuttavat kuuden päivän iän, robotti vie taimet kameran kuvattavaksi kuusi kertaa neljän tunnin välein. Kasvien kuvaaminen tapahtuu täysin pimeässä laatikossa, jossa erittäin tarkka kamera kuvaa kasveja sen jälkeen, kun niille on annettu sinisen valon LED-pulssi. Kasvien reaktiosta LED-pulssiin saadaan mitattua aikaisemmin esitelty klorofyllin fluoresenssi. Samalla kuvista kerätään myös muuta informaatiota, kuten esimerkiksi lehtipinta-ala sekä luontainen vuorokausirytmi. Jokainen taimi on yksilöity RFID-teknologian avulla, joten sadonkorjuun jälkeen voidaan tutkia kuudentena päivänä mitattujen ominaisuuksien ja lopullisen tuorepainon yhteyttä. Jos diagnostiikkarobootti käy lähes täydellä höyryllä, vuoden päästä kasassa kunnioitettava otos: yli 2miljoonaa dataparia yksittäisen kasvin ominaisuuksista päivänä kuusi, sekä saman kasvin lopullinen tuorepaino.

Tekoäly hoitaa tilastotieteilijän työt

Tiedonkeruuvaiheen jälkeen japanilaistutkijat laittoivat neuroverkon töihin. Kuvausvaiheessa jokaisesta kasvita oli kerätty tiedot yhteensä 16 erilaisesta biologisesta ominaisuudesta. Seuraavaksi tutkijat ajoivat datan 40 kertaa neuroverkon läpi. Neuroverkko muodosti datasta regressioyhtälön, jossa selitettävänä muuttujana käytettiin salaatin lopullista tuorepainoa ja selittävinä muuttujina edellä mainittuja havaittuja biologisia ominaisuuksia. Neuroverkko selvitti jokaisen yksittäisen selittävän muuttujan korrelaatiokertoimen tuorepainoon sekä standardivirheen. Yksittäisistä selittävistä muuttujista suurin korrelaatiokerroin löytyi klorofyllin fluoresenssista sekä lehtipinta-alasta.

Regressioyhtälön korrelaatiokertoimeksi saatiin lähes 0,5, eli mitattujen ominaisuuksien avulla pystytään selittämään lähes 50% satotason vaihtelusta. Neuroverkon luoman mallin pohjalta pystytään siis tehokkaasti arvioimaan jokaisen salaattiyksilön odotusarvo jo kuuden päivän iässä. Salaattitehtaan pyörittäjän päätettäväksi jää se, minkä odotusarvon alittavat salaatit poistetaan kasvatusalustalta tässä vaiheessa. Kun raja-arvot on määritelty, diagnostiikan hoitava robotti poimii automaattisesti huonot yksilöt pois kasvatusalustalta ja korvaa ne paremmilla yksilöillä toisilta tarjottimilta, kunnes jäljellä on enää valioyksilöitä, jotka siirretään varsinaiseen kasvatustilaan loppukasvatusta varten. Koska salaatti vaatii hyvin vähän tilaa sekä valoa ensimmäisen kuuden päivän aikana verrattuna seuraavaan noin 30-40 päivään, matalan odotusarvon yksilöiden poisheittäminen päivän kuusi kohdalla parantaa salaattitehtaan kannattavuutta sekä ekologisuutta huomattavasti. 

Kyseinen esimerkki osoittaa, miten kohtuullisen pienellä investoinnilla voidaan parantaa Plant Factorien tuottavuutta yhdistämällä tekoälyä, robotiikkaa sekä kekseliäisyyttä. Tulevaisuudessa tekoäly tulee varmasti parantamaan plant factorien managereiden päätöksentekoa vielä hyvin monilla muilla tavoilla. Kasviyksilöiden analytiikka voi tulevaisuudessa mahdollistaa esimerkiksi tekovalo- ja ravinnereseptien optimoinnin yksilötasolla.

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