Electronic Thermostat for Fridge
Introduction
Thermostats are a usual method of sensing a temperature of a system and maintain the system’s temperature at a predefined point. The most popular and ubiquitous appliance in any home is a Refrigerator. A thermostat maintains the pre-set value of temperature by switching the heat conduction. In short, it regulates the heat flow. In Physics, there is no such thing as cold, its either higher temperature or lower temperature – heat flow (absorption or dissipation). Thermostats are a regular feature in Air Conditioner, Microwave Ovens, Ironing machines, Induction Heaters and Refrigerators in home appliances category. At the same time in many scientific labs (biology, physics or chemistry research domains) storing experimental samples (veils, substrates, materials etc.) these above appliance have a larger role to play. Most of these laboratory experiments run for weeks and such appliances run almost 24x7. Maintaining the pre-set temperatures are an integral part in such labs.
In case of residential utilities due
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The noninverting input of the comparator is applied to a reference voltage derived from a zener diode VZ1 which is then further divided by the potential divider arrangement provided by R7, R9 & P1. C4 is the decoupling capacitor to bypass AC noise if any.
Heart of the circuit - Between the inverting input and the ground is the temperature sensor. The temperature sensor here is an NPN silicon transistor with it collector shorted to its base. The transistor’s temperature dependent characteristics of base-emitter junction is used as temperature sensing property. For every degree rise the junction voltage decreases by 2mV. Potentiometer P1 is adjusted to the reference voltage at a value equal to the sensor’s junction voltage corresponding to the less negative temperature if the two extremes (-5V0C in the present
Thermodynamics is essentially how heat energy transfers from one substance to another. In “Joe Science vs. the Water Heater,” the temperature of water in a water heater must be found without measuring the water directly from the water heater. This problem was translated to the lab by providing heated water, fish bowl thermometers, styrofoam cups, and all other instruments found in the lab. The thermometer only reaches 45 degrees celsius; therefore, thermodynamic equations need to be applied in order to find the original temperature of the hot water. We also had access to deionized water that was approximately room temperature.
The MCE is typically in the range of (1-5) k/T (in terms of the adiabatic temperature change). This modest change in temperature is obviously not sufficient for applications such as domestic refrigeration etc. [24].
Above is the view for the analog switch we will be using. This analog switch has 8 pins but for our purposes, we will be using pins 3 and pin 6 so the switch could receive the signal of any wetness that has been detected. The other pins that we will be using from this switch are the output pins which are pins 1 and 8 in the circuit above. These output pins will be connected to the next part of the experiment which is the encoder. [2]
The purpose of the lab is to understand how to calculate the calorimeter constant by using a calorimeter. This allows us to analyze the heat reaction of different substances. Calorimetry is a word that comes from both Latin and Greek. The prefix “Calor” in Latin signifies heat and the suffix “metry” in Greek means measuring. Therefore the word itself translates to measuring heat. Joseph Black, was the first scientist to recognize the difference between heat and temperature. Energy is always present in chemical and physical changes. The change of energy that occurs when there is a chemical change at constant pressure is called enthalpy. Enthalpy changes , as well as physical and chemical changes, can be measured by a calorimeter. The energy that is released or absorbed by the reaction can be either absorbed or released by the insulating walls of the instrument.
We must first begin the today’s lab by connecting the thermometer that digitally detects surrounding temperature to the Lab Pro Interface located on the computer via...
Refrigeration, the production of cold, is an essential practice for present-day living. It is used in a many place like the processing and preservation of food, conditioning of air for comfort, manufacture of chemicals and other materials, cooling of concrete, medical applications etc. Refrigeration is defined as the science of maintaining the temperature of a particular space lower than its surrounding space. Refrigeration and air conditioning involves various processes such as compression, expansion, cooling, heating, humidification, de-humidification, air purification, air distribution etc. In all these processes, there is an exchange of mass, momentum and energy. All these exchanges are subject to certain fundamental laws. Hence to understand and analyses the refrigeration and air conditioning systems, a basic knowledge of the laws of thermodynamics, fluid mechanics and heat transfer is essential.
Refrigeration is the process of cooling down a space or thing below normal environmental temperature. Food preservation is vital in today’s day and age. From the meats to the dairy, everything needs to be kept at room temperature, cold, or frozen. People even like to make themselves cold and frozen by using air conditioning. But, it does make you wonder “how” and “when”. How did refrigeration become such an important invention and how did people survive without it? When did our ancestors realize it takes the cold to keep their food preserved and looking fresh? We now have fridges that have an automated ice machine and touch screens.
Transducers contain the crystal lead zirconate titanate, designed and fitted into the probe in thin, rectangular slabs referred to as elements. A conducting layer of silver covers the front and back faces of each element forming electrodes and having electrical leads attached where the alternating voltage is applied.(Fairhead and Whittingham, 2012)
The purpose of the lab was to show the effect of temperature on the rate of
Refrigeration Refrigeration is defined as “The process of removing heat from an enclosed space, or from a substance, to lower its pressure.” (First website given in bibliography) In simpler terms, it is removing heat from states of matter in order to keep them cooler. The basic need for refrigeration is to cool food and beverages, as they often get spoilt if the temperature is high. Before actual refrigerators and other such mechanical systems were introduced, it was very common for people to cool their food with ice and snow.
Quantum thermodynamic scientists are aiming to explore the behavior outside the lines of conventional thermodynamics. This exploration could be used for functional cases, which include “improving lab-based refrigeration techniques, creating batteries with enhanced capabilities and refining technology of quantum computing.” (Merali P.1). However, this field is still in an early state of exploration. Experiments, including the one that is being performed at Oxford University, are just beginning to test these predictions. “A flurry of attempts has been made to calculate how thermodynamics and the quantum theory might combine” (Merali P. 1). However, quantum physicist Peter Hänggi stated that “there is far too much theory and not enough experiment” (Merali P.1) in this field of study, which is why its credibility is undermined. Nevertheless, people are starting to put more effort into understanding quantum thermodynamics in order to make
The greenhouse effect results from the heat energy of sunlight being absorbed by the Earth and molecules in the Earth's atmosphere ( Figure 1 ) . This energy is usually radiated back towards space. However, as we change the gases in the Earth's atmosphere as the results of everyday living, this energy is unable to leave the Earth's atmosphere and is trapped as heat. The heat causes a gradual warming of the air around the Earth. This warming is known as the greenhouse effect.
It is where it uses biomolecules from organisms such as enzymes, antibodies, nucleic acid and a cell as a whole. It is design to interact with the specific analyte of interest to produce an effect measurable by the transducer.
In thermodynamics Refrigeration is the major application area, in which the heat is transferred from a lower temperature region to a higher temperature region. The devices which produce refrigeration are known as Refrigerators and the cycle on which it operates are called refrigeration cycles. Vapour compression refrigeration cycle is the most regularly used refrigeration cycle in which the refrigerant is alternately vaporized and condensed and in the vapor phase it is compressed. Gas refrigeration cycle is the well-known refrigeration cycle in which cycle refrigerant remains in the gaseous phase throughout the cycle. Cascade refrigeration are the other refrigeration cycles discussed in this chapter; absorption refrigeration is the one more refrigeration cycle which is used where the refrigerant is dissolved in liquid before it is compressed. One more refrigeration in which refrigeration is produced by passing the electric current through two dissimilar materials is called as the thermoelectric refrigeration.
to work because it will not be at the optimum temp, or it will not