Sökresultat:
1540 Uppsatser om Heat flow - Sida 2 av 103
Utvärdering av ett värmepumpsystems prestanda till en HWC-tvättmaskin : Med fokus på fläktvarvtal och köldmedieflöde
This report was performed in order to evaluate a new technological measure and focuses generally on a heat pump system to a HWC-washing machine. The client is Asko Appliances AB, a company well known for its environmentally friendly products. The goal of this study was to improve the energy efficiency of a washing machine by combining a heat pump device to the heater of the wash water, in order to reduce the energy consumed for heating the water. Besides reducing the energy consumption in heating the water, the washing machine was required to meet low noise and short operating time specifications. For that purpose, nine trials in three test series have been carried out.
Frånluftsvärmepumpens möjligheter i flerbostadshus
If a building is heated by a heat pump, it is of high importance that the heat pump has a high coefficient of performance. An exhaust air heat pump extracts heat from the building?s exhaust air. The air has a relatively high and constant temperature all year around, leading to a high seasonal coefficient of performance. This thesis examines whether it is profitable to complement an exhaust ventilation system with an exhaust air heat pump in an apartment block that already has geothermal heat pump, district heating, oil- or biofuel heated system.
Turbinkretspump system - Kraftvärmeverket i Borås
The Rya power plant in Borås produces district heating, district cooling and electricity. The plant is owned by Borås Energi och Miljö AB and is run by Dalkia Facility Management AB.In order to get the best heat exchange from the district hot water a pair of twin pumps and a turbine circuit pump are used as return pumps. Turbine circuit pumps are used to increase the pressure through the heat exchangers at the power plant. The pumps are in use when the flow is over 2 000 m3 h-1 and during the summer when re-cooling is used to improve the effectivens of the heat boilers.Since the pumps, that are parallel connected, rotating at a fixed rate per minute, the pressure is regulated with regulating valves. This report shows that during the 4,300 hours that the pumps where in use, energy corresponding to 590 MWh was wasted.
Ny teknik för småskalig kraftvärme : - med fokus på Organisk RankineCykel (ORC)
As a part of the fight against the global warming the energy production needs to be more efficient and redirected towards sustainable options. One alternative is cogeneration, which means that electricity and heat is produced in one plant. The purpose with this survey is to examine if there are any commercial available combined heat and power techniques, based on combustion of solid moist biomass, which are suitable to small-scale applications. The technique must be able to produce between 2 and 10 MW thermal and the heat demand is a Swedish district-heating system. When already published reports had been studied, the Organic Rankine Cycle (ORC) was chosen as the most suitable technique.
Värmeöverföring i bergvärmesystem : En numerisk analys av den ringformade koaxiala borrhålsvärmeväxlaren
The borehole heat exchangers of today suffer from poor thermal and hydrodynamic performance. The purpose of this thesis is to improve the performance of ground source heat pump systems and thermal energy storages by increasing the energy efficiency of the borehole heat exchangers. For this reason, the annular coaxial borehole heat exchanger (CBHE) has been analyzed. This type of heat exchanger is interesting in terms of both thermal and hydrodynamic performance. A model has been set up in the program Comsol Multiphysics in order to investigate the heat transfer characteristics along the borehole.
Betydelsen av flow i bildskapande och pedagogers betydelse för flow : En uppsats inom bildpedagogik om flow och kreativitet och vilka förutsättningar som gynnar flow.
Uppsatsen behandlar ämnet genus och genusframställningen i barnböcker nu, och för 50 år sedan. För att komma fram till ett resultat har två analysmetoder använts, Nikolajevas mimetiska metod samt en semiotisk bildanalysmetod. Resultatet visar att det skett en förändring av genusframställandet i barnböcker de senaste femtio åren och att den största förändringen skedde i mitten på 60-talet..
Vibrationsdämpning av värmepump
Thermia Värme AB is one of the market leading manufactures of heat pumps. In order tomaintain this position, the company wants to improve the vibration characteristics of theirproducts. The aim of this thesis is to develop product design changes that lead to a reductionof vibrations in the heat pump Thermia Diplomat 8.The main cause for vibrations in the system is flow pulsation and mechanical forces inducedby the scroll compressor. Vibration is transmitted through the compressor piping and receivedby the heat exchangers, from where it is further transmitted to the connection points for theradiator and heat source circuits.A number of design changes in order to improve the vibration characteristics have beenevaluated through calculations and practical experiments. The changes have included thecompressor and heat exchanger mountings, the compressor suction and discharge line pipingand also pulsation dampening.The results of the experiments show that the vibration levels in the connections for the heatingand brine circuits can be decreased strikingly through changes in suction and discharge linepiping.
Restvärmeåteranvändning från absorptionsvärmepumpar : en kartläggning av möjligheter och begränsningar vid Vattenfall Värme Uppsala Block 5
Vattenfall district Heating power plant in Uppsala produces district cooling with absorption heat pumps which leads to a large amount of waste heat that has to be cooled with evaporative cooling towers. The Environmental Court has ordered Vattenfall to survey the possibilities to recover the heat, which is the focus of this thesis.The study begins with an overview of the system, and conditions and limitations for waste heat recovery is examined. In the next step alternatives to recycle the heat is evaluated, either by direct recovering or by upgrading.First, the technical possibility of each alternative is discussed, and then the operation time and the amount of recovered heat is calculated. Those alternatives which are possible are brought further to an economic analysis.The cost of investment for each alternative constitutes the basis for a present value analysis. The results are put together in a table where the total amount of recovered heat is compared with the present value for the different alternatives.
Konstruktion av patientsimulator för anestesimaskiner
A patient simulator for testing anaesthesia machines has been developed at Maquet Critical Care AB, to reduce costly and time-consuming experiments on animals. The device simulates human lungs regarding lung dynamics and volume, uptake of anaesthetic agents and the production of carbon dioxide, heat and moisture. Further demands on the simulator are durability and size; the device shall be compact enough to be moveable.The resulting simulator fulfils the requirements and enables better repeatability and ability to test extreme cases than experiments on animals do.Uptake of the anaesthetic agent is achieved in a active carbon filter and controlled by regulating the flow. The flow is created by a regenerative blower and controlled using a proportional valve. The uptake can be set by the user or by a simple uptake model modified to recursively handle changes in the concentration of anaesthetic agent.Carbon dioxide is fed into the system from a tank by a mass flow regulator.
Datormodellering av en värmelagrande betongväggs inverkan på det termiska klimatet i ett växthus
This report describes the building of a computer model that makes it possible to simulate the thermal climate in a greenhouse. The computer model is built on the physical theory of heat exchange that occur in a greenhouse, such as radiation and convective heat exchange. The model also includes the heat storage that is active in a greenhouse.The computer model is used to simulate the thermal climate in a greenhouse under three periods, winter, spring and summer. It also investigates which effect a concrete wall has on the thermal climate in a greenhouse. The purpose of putting a concrete wall in the greenhouse model is to investigate the possibility to store heat during the day and then use this heat when the temperature drops during the night.The result from the simulations shows that a concrete wall levels the big difference in temperature that normally occurs under a day in a greenhouse.
Värmepumpars inverkan på elkvaliten
Modern technology and fast development of heat pumps, the hunt for savings in energy consumption and the strive for environmentally friendly energy sources, convenience, and financial profit, have made heat pumps a reasonable alternative for the heating of houses.When the heat pump starts it will consume a considerable amount of current, which may result in a short-lived voltage-drop if the power grid is weak compared to the start-up current.The company Fortum Distribution which owns and administrates electrical network is interested in an investigation that deals with heat pumps affect on the quality of electricity.The purpose of this investigation is to study fast electrical fluctuations (flicker) as a result of start-up currents for single as well as multiple heat pumps on the same electrical station and from this evaluate whether there will be any problems installing heat pumps..
Värmestyrning I Handske
This rapport is result of a project. The purpose of which was to design a circuit that is used in a heat glove. The heat glove is the technical aid which provides heat inside a glove.It is specially suited for old people who have problems with cold hands because of decreased blood circulation.There already was an old circuit in the glove that gives a constant current which develops heat from battery to glove through a circuit. The temperature is between 32 and 34 degrees.The problem with the existing circuit was to regulate the temperature. There is only on/off switch and there is no way to adjust desirable value of the temperature.In order to solve the problem the old circuit was investigated.
Inventering av värmelager för kraftvärmesystem
When a combined heat and power plant produces heat and power it often faces a deficit of heat load during the summer or other periods of time. This heat is often unnecessarily cooled away or the power production has to be reduced or shut off. If it is possible to store heat from periods with low heat demand to periods with high heat demand one can get many benefits. Among these benefits are: increased power production, decreased operation with partial load, uniformly distributed load.To be able to store heat in situations like this long-term thermal heat storages are needed. In this thesis five different types of stores are presented: rock cavern storage, tank storage, pit water storage, borehole storage and aquifer storage.
Samkörning mellan värmepumpar och fjärrvärme : Bostadsrättsföreningen Bogården
This diploma work covers an investigation over the heat - and hot water systems of thetenant-owner's association, Bogården. The heat - and hot water needs of Bogården aresatisfied by both district heating as well as three heat pumps. Implemented investigationshows that the heat pumps are not used in a profitable way. Apart from that, the reservepossibilities are small. There is also a risk of the growth of Legionella bacterium in thehot water system.Since the heat pumps are already installed, HSB-Gävleborg (responsible for Bogården)has a wish to investigate possible proposed actions for optimization of existing plant.After completed investigation, a new proposed action is presented.
Potentialen av värmebesparing i ett avlopps luftningsledning
This thesis aims at determining the heat losses in a property vent stack and its roof valve. Upon request of a company, the vent stack is analysed for possible heat recovering solutions to be implemented, while relining of the drain system is executed and with a suitable payback time for the economic investments. The heat loss calculations are based on data for properties that are located in the Stockholm region, but also easy to change depending on the situation. The calculations are done on pipes made out of cast iron, which still is the most common type of drain pipe in Sweden, and these are the pipes that relining is usually made on. The calculations that needed to take several variables into account have been done in MatlabR2014a and the thermos dynamical properties that were used in those calculations have been extracted from EES.Three different types of heat losses in the vent stack have been taken into consideration in this thesis.