Heat storage

Name : Mihwa Kang

Lab Partner : Min Ah You , Kwang Yoeul Yoon

Lab Section : C117 , Thursday , 11 :15 AM

AI : Zack Forsyth

Date : October 26 , 2006

HEAT STORAGE FOR SOLAR HEATING

Objectives

To learn about Solar Thermal Energy and heat storage devices

To learn about a technique called calorimetry

To measure the heat of fusion of Sodium thiosulfate pentahydrate Na2SO2 . 5H2 O

To evaluate the feasibility of this salt for heat storage

Introduction World 's energy resources are being exhausted at a very rapid rate . Now the

world is looking for developing a diversity of cleaner and renewable energy sources and energy conservation due to energy shortage and environmental reasons . Future lies in nuclear energy and renewable sources such as solar power . In this experiment , you well explore a chemical method for storing solar energy

Solar Thermal Energy . Sun is a greatest energy source which needs proper utilization . Harnessing energy needs efficient and inexpensive technologies which do not exist at present . The two methods for altering solar radiation into electricity and heat are

Photovoltaic Cells . They are made of silicon alloys and convert sunlight directly to electricity

Solar Thermal Heat . This technology utilizes solar collectors to heat a fluid The huge solar energy plants employ hundreds and thousands of flat tracking mirrors to produce electricity , which is indeed and expensive technology . World 's largest Solar power station Solar One ' used the technology of storing solar energy in a tank filled with rocks and sand and oil was used for heat transferring . On the same theme , in this experiment , in this experiment , we explored a solar energy storage system based on the low melting salt , sodium thiosulfate pentahydrate Na2SO2 . 5H2 O Heating and Cooling Curves . In the figure 1 given below , the changes in the temperatures of substances with changing states of substances , is illustrated . With the addition of heat (Enthalpy of fusion ) a material changes from solid through liquid to the gaseous state and vice versa Figure 1 . heating Curve for Solids1

An experiment was conducted to explore the feasibility of using a salt Sodium Thiosulfate pentahydrate for storing solar energy . This salt has a low melting point (48o C . It changes quickly into crystals and is easy to poured into heat storage containers

Calorimetry . Calorimetry is performed by using a calorimeter for measuring the heat released during solidification process of substances

Experimental Procedure

The experiment was performed using the calorimetry method , the readings were taken and then the result was compare against the database for other salts ' latent heat of fusion . In to measure the heat storage capacity , the molar heat of fusion2 for sodium thiosulfate pentahydrate was measured using a Styrofoam cup filled with water as the calorimeter . The amount of water in the cup and its temperature was measured . The molten salt of known mass /weight was poured into the water it started freezing and heat started releasing into the water The change in the temperature due to this process was noted at equal intervals of time...