Seabed sediment : a natural seasonal heat storage feasibility study

The new discovery among renewable energy resources, seabed sediment, has been utilised as a heat source for 42 houses in Vaasa since 2008. Sediment heat is annually loaded by the Sun. In this study the amount of annually charged energy is estimated. The difference of sediment temperatures between the coldest and the warmest month during the year is a key value in the approximation of the loaded energy. Sediment temperatures are measured once per month via optical cable by distributed temperature sensing (DTS) method. The monitoring period is three years, 2014–2016. The estimation of incoming energy (575 MWh) versus known exploited energy (560 MWh) is reasonable. Despite of the extraction this seasonal heat storage in the seabed of the Baltic Sea seems to reload well annually.fi=vertaisarvioitu|en=peerReviewed

Thermal Response of Multiple Pipes and Fluids Using COMSOL for Geothermal Energy System Application

A geothermal system is modeled using COMSOL. The purpose is to study and evaluate the thermal response of the pipes and the fluids. The model is designed for a low energy network. A part of this network is used to collect energy from a sediment layer under water body. This model depicts a heating system in the low energy shallow network which brings out the thermal response and helps implementing an efficient geothermal system application. This model executes in COMSOL on a special pipe dedicated as a heat collector for the heating system, to study the heat transfer within the pipes and the fluids used as a heat carrier. It also presents the thermal response of multiple fluids and compares the simulated and the measured data of the actual working fluid within the system. The temperature distribution and the heat flux along the length of the pipe are also taken into account in multiple pipes.©2014 NAUNfi=vertaisarvioitu|en=peerReviewed

Perhekeskus Tyrnävälle – Monialaista yhteistyötä kehittämässä

Lapsi -ja perhepalveluiden muutosohjelma (LAPE) oli yksi Juha Sipilän hallituksen kärkihankkeista vuosille 2016–2018. Uusi hallitusohjelma jatkoi LAPE -muutoshanketta kausille 2020–2023. Lapsi- ja perhepalveluiden muutosohjelman tavoitteina ovat nykyistä lapsi -ja perhelähtöisemmät, kustannustehokkaammat ja vaikuttavammat palvelut, joissa palvelujen yhteensovittaminen on ensisijaista. Perhekeskustoimintamalli verkostoi ja sovittaa yhteen nyt erillään olevat lapsiperheiden palvelut siten, että jokainen lapsi ja perhe saa tarvitsemansa tuen ja avun samasta paikasta. Tutkin pro gradu - tutkielmassani perhekeskustoimintamallin vaikutuksia monialaiseen yhteistyöhön hankeorganisaation henkilöstön käsitysten perusteella. Perhekeskustoimintamalli sitoo yhteen monialaisen ja sektorirajat ylittävän yhteistyöverkoston, jonka käyttöönotto vaatii työkulttuurin muutosta toimijoilta. Tutkielmani tuloksia arvioitiin kunnan hankeorganisaation toimijoiden näkökulmista. Monialainen hankeorganisaatio koostuu sosiaalialan, terveydenhuollon, mielenterveystyön, sivistystoimen ja kolmannen sektorin toimijoista. Tutkimus on fenomenologinen tutkimus, jonka tehtävänä oli selvittää työntekijöiden käsityksiä muutoksen vaikutuksista monialaiseen yhteistyöhön. Teoreettisena viitekehyksenä tutkimuksessa on työnkehittäminen. Tutkimuksen aineisto on kerätty haastattelemalla kuutta (6) hankeorganisaatioon kuuluvaa työntekijää Tyrnävän kunnasta. Aineiston analyysimenetelmänä olen käyttänyt sisällönanalyysiä. Tulosten mukaan hankeorganisaation toimijat kokivat, että mahdollisuuksia monialaisen yhteistyön tekemiseen on olemassa, mutta se vaatii onnistuakseen kehittämistä ja työkulttuurin muutosta tietoa jakavaan ja systeemiseen orientaatioon. Perhekeskustoimintamallin vaikutuksista toimijoiden käsitykset olivat samansuuntaisia. Malli lisää asiakkaiden tasa-arvoista kohtelua ja tasapuolisuutta, sekä madaltaa kynnystä hakeutua palveluiden piiriin. Uhkana työntekijät näkivät eri organisaatioiden sitoutumattomuuden sektorirajat ylittävään yhteistyöhön ja siirtymisen tietoa jakavaan työkulttuuriin. Työnkehittämisen näkökulmasta työntekijät kokivat, että mallin juurruttaminen toimintatavaksi vaatii sinnikästä työskentelyä, kehittämismyönteistä asennoitumista, vahvaa johtamista ja halua sitoutua perhekeskustoimintamallin tavoitteisiin

Seabed Sediment as an Annually Renewable Heat Source

Thermal energy collected from the sediment layer under a water body has been suggested for use as a renewable heat source for a low energy network. A prototype system for using this sediment energy was installed in Suvilahti, Vaasa, in 2008 and is still in use. It provides a carbon-free heating and cooling solution as well as savings in energy costs for 42 houses. To be a real, renewable heat source, the thermal energy of the sediment layer needs to replenish annually. The goal of this paper is to verify the possible cooling or annual heat regeneration. The sediment temperatures were measured and analyzed in the years 2013–2015. The data were compared to the same period in 2008–2009. All measurements were taken in the same place. This paper also confirms the potential of the sediment heat, especially in the seabed sediment, using the temperature differences between the lowest and the highest values for the year. The results demonstrate that the collection of the heat energy does not cause permanent cooling of the sediment. This result was obtained by calculating the temperature difference between measurements in the warmest month and the month with the coldest temperatures. This indicates the extracted energy. The difference was found to be around 9.5 °C in 2008–2009, rising to around 11 °C for the years 2013–2014 and 2014–2015. This indicates the loaded energy. The energy utilization is sustainable: the sediment temperature has not permanently decreased despite the full use of the network for the heating and cooling of houses between 2008 and 2015.fi=vertaisarvioitu|en=peerReviewed

A preliminary test for using a borehole as cool storage

This paper describes a preliminary test for using a borehole as a cool storage. The testing was done using a dry borehole in Vaasa area. The cooling was done using a special trailer in period of 9 days after which the borehole was allowed to warm naturally up. Temperature data was collected both cooling and warming periods. The temperature of undisturbed ground had not reached the original bedrock temperature even after 12 days. The temperature data collected also indicate that one can store cool in a similar way as the heat around a borehole. This test did not cause any visible damage to bedrock that is important when making a cool storage.fi=vertaisarvioitu|en=peerReviewed

Numerical simulation of heat recovery from asphalt pavement in Finnish climate conditions

A 3-dimensional mathematical model of asphalt pavement system was developed, based on the fundamental energy balance, to calculate temperatures beneath asphalt surface using hourly measured solar radiation, air temperature and wind velocity data. The modelling was conducted to predict the heat retention under the asphalt surface to seek an optimum position of pipe tubing to maximise the heat extraction considering the Nordic winter conditions for future infrastructure projects. The model results show good agreement with the experimental results conducted in a span of three months (June–Sept) notwithstanding the simplification of the model i.e. thermal properties unaffected by changing moisture content, perfect contact between different layers and homogeneous and isotropic thermal properties of materials (asphalt, sand and gravel). The findings indicated that the positioning of the heat extraction tubes under the asphalt layer will be dictated by the application. For heat extraction, pipes closer to the surface are ideal for maximal heat absorption during summer, however, in winter the outer temperature may effect properties the pipes. Parameters including pipe diameter, positioning of the pipes and flow rate were analysed. Temperature increase of up to 10 °C gain was observed for piping closer to the asphalt layer and 6 °C for pipes position at deeper from the asphalt layer. This model could be used in future to optimise critical variables for successful implementation of asphalt heating concepts.© 2023 The Author(s). Published by Elsevier Masson SAS. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).fi=vertaisarvioitu|en=peerReviewed

Analysis of ground heat exchanger for a ground source heat pump : A study of an existing system to find optimal borehole length to enhance the coefficient of performance

Ground Source Heat Hump is one of the emerging technic to utilize the reservoir of geothermal energy in Europe. The crucial factor is to find the optimal length of the borehole to successfully design a heating system. The length of the borehole varies depending on the geographical area, the capacity of the heat pump and heat load of the desired building in consideration. Several methods have been theorized and validated using the experimental measurements to find the optimal length of the borehole. The most commonly used methods are American Society of Heating, Refrigeration and Air-conditioning Engineers and International Ground Source Heat Pump Association for sizing borehole heat exchanger. In this paper, an existing system is analyzed, for a 60 kilo Watts heat pump in an area of Finland with a ground source 250 meters of Borehole Heat Exchanger. Coefficient of Performance for current scenario is calculated, an optimal length is found for the heat capacity of the heat pump to enhance the performance of the system. Improved coefficient of performance is presented along with an easy method of finding the optimal length of the ground source.fi=vertaisarvioitu|en=peerReviewed

Seasonal temperature variation in heat collection liquid used in renewable, carbon-free heat production from urban and rural water areas

A renewable energy source called sediment energy is based on heat collection with tubes similar to those used in ground energy and is installed inside a sediment layer under water body. In this paper, an investigation of temperature behaviour of heat carrier liquid is made during several years to evaluate utilization of sediment energy. This is done by evaluating temperature variations of heat carrier liquid and its correlation to air temperature. This increases advancement of knowledge how the temperature of the sediment recovers from the heat collection. The temperature variation of the liquid seems to correlate with the mean monthly air temperature. The selected methods clearly indicate that sediment energy seems to be yearly renewable because there is a clear correlation between air temperature and heat carrier liquid temperature.© Authors. This is an open access journal distributed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0)fi=vertaisarvioitu|en=peerReviewed

Low-power Renewable Possibilities for Geothermal IoT Monitoring Systems

Nowadays, humanity is facing a difficult challenge, because of sustainable energy use and production. One of the major ways to solve this problem is the usage of renewable energy as a sustainable and reliable source of electric power and heat. This trend is also obvious in the field of the Internet of Things (IoT), where research teams are increasingly focusing on renewable energy and its monitoring with IoT. This paper aims to map current research on the use of the Internet of Things with a special focus on use in geothermal applications. Information concerning renewable geothermal energy sources and individual IoT communication technologies is summarized. A basic Bluetooth iBeacon test case is also presented.©2022 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.fi=vertaisarvioitu|en=peerReviewed