HOT WATER ON DEMAND

Portfolio Activity! This counts toward your final grade!


What are my objectives while studying this topic?


In this section you will learn how domestic hot-water systems work, and how science is used to maximise their efficiency.


Why is this important?


Hot water on demand; this is something the vast majority of us take for granted. We turn on a tap and large amounts of hot water can be accessed almost immediately. In some parts of the world, however, creating hot water is an extremely labour and time-intensive process.


Conduction Convection Radiation

Hot water is vital to us; we use it to cook, clean, bathe, drink and in many modern households we use it as a heat source via a central-heating system. Without an automatic and regulated supply of hot water, our comfortable lives would be very different.


Can I get an introduction to this topic?


Yes, why not have a look at the following clip.



How do hot-water systems work?


Modern domestic hot-water systems are fantastic pieces of engineering, condensing boilers for example can be over 90 per cent efficient! But how do they work, how do they deliver hot water for cooking and cleaning, as well as hot water for heating? Check out the following link:


 

Combination of combi boilers
System Boilers
Open Vent Boilers

 

Let’s get to it: what do I need to do?


The following pieces of work count towards your Portfolio Grade!


Activity 1


Domestic Hot Water


In this portfolio activity, which forms part of the assessment for this Unit (Report b: ‘A report on the application of domestic energy and the community, including the formation, extraction and use of a fossil fuel in the context of a domestic hot water heating system report and the impact of two (2) energy related organisations involved with this process’), you need to find out in detail about Domestic Hot Water systems.


You need to examine a household hot water system, and explain in detail how energy is transferred from the fuel (electricity, oil or gas), to the water, and how the water is then pumped around the house, including, if appropriate, how the hot water is used to heat a house as part of a hot-water central heating system.

 

You need to produce a large (double-sided), A3 sized, annotated diagram of a real domestic hot water system. Each section of the system needs comprehensive and detailed explanations of the following:


The mechanisms of thermal energy transfer: conduction and convection in terms of particles; and radiation in terms of emission and absorption of infra-red electromagnetic waves; all in the context of a domestic hot-water system


[Help: Higher level work will involve comprehensive, detailed written and diagrammatic explanations of how thermal energy is transferred from the fuel (or electrical heater) to the water, and how thermal energy from the hot water is transferred from radiators to the rooms of a house]


How the Zeroth Law of Thermodynamics can be used to explain thermal energy transfer within a domestic hot water system


[Help: Once you have found out what the Zeroth Law of Thermodynamics is, you need to explain, both in text and diagrammatically, how the Zeroth Law governs thermal energy transfer, and how this is applied to a domestic hot water system]


How the domestic hot water heating system works and is controlled and explain how the processes of heat transfer are used to maximise it's effectiveness and efficiency
[Help: In this section, you need to annotate your diagram to show how the temperature of the hot water, and the temperature of different rooms is monitored and controlled.

This will involve explaining the feedback loop between the heating system and the thermostats. You also need to include information about how the efficiency of the whole system can be maximised, including considerations of insulation and (intelligent) computer control]


Presentation – Your annotated diagram needs to contain a mix of graphics and text. Think about the audience of the report – how can you present your diagram with impact and clarity? This forms part of the assessment for this piece of work (see below).


Open the download to take a look at how you’ll be assessed.



Activity 2



What’s the temperature?


Radiator

In this portfolio activity, which forms part of the assessment for this Unit (Report b: ‘A report on the application of domestic energy and the community, including the formation, extraction and use of a fossil fuel in the context of a domestic hot water heating system report and the impact of two (2) energy related organisations involved with this process’), you need to investigate experimentally, the link between the surface temperature of a room radiator and the air temperature of the room.

Thermometer

 

You need to set-up a data-logger with at least TWO thermometer probes. One thermometer probe needs to be attached to a radiator, and the others need to be placed around the room, systematically away from the radiator. The temperature then needs to be logged over 24 hours of normal use when the radiator is working.

 

The temperature of each probe needs to be recorded every 10 minutes or so, and then the results need to be presented in a suitable format.

 

You then need to analyse and explain the patterns in the data. In particular, you need to examine the temperature difference(s) between the probe on the radiator and the other probe(s).

 

Explain any patterns that you get in terms of the Zeroth Law and the mechanisms of heat transfer.

 

Think carefully about how you present your data, making sure that it is clear and logical. There needs to be clear links between the presentation of the data and the analysis and explanations.

 

Open the download to take a look at how you’ll be assessed.



Activity 3


How much could you save?

 

Roof insulation

In this portfolio activity, which forms part of the assessment for this Unit (Report b: ‘A report on the application of domestic energy and the community, including the formation, extraction and use of a fossil fuel in the context of a domestic hot water heating system report and the impact of two (2) energy related organisations involved with this process’), you need to research the link between the economics of domestic hot water and heating and the environment.

 

Gas Bills

Insulating your house will save you money and reduce your ‘Carbon Footprint’. Switching energy suppliers could also save you money.

 

Use the following websites to find out how much you could save per year by adopting good insulation systems in your house. The websites will also give you details about the amount of CO2 saved per year – reducing the effect of Global Warming. By how much could you reduce your carbon footprint? How long would it take to payback on the investment of the insulation techniques?

 

Websites:





 

For your house:


1.Find out how much your current fuel bills are and how much you could save by switching supplier.


2.Find out: which insulation systems you could fit to your house; how much they would cost to install; how much you could save per year; the pay-back time and how much CO2 would be saved per year.


3.What have you found out? What are the potential consequences of your findings? What is your evaluation of this data?



Open the download to take a look at how you’ll be assessed.



Activity


Part of your assessment requires you to use other people’s work, such as adapting standard procedures or finding out and using information on the internet. When you use information like this you need to reference it properly in your reports. The following link takes you to a suitable method for referencing:

 


Portfolio Follow-up

 

Portfolio work will be marked in accordance to the appropriate assessment criteria:


 

What are the key words to learn and use?


  • Conduction

  • Convection

  • Radiation

  • Zeroth Law

  • Efficiency

  • Insulation


What will I be expected to be able to do after studying this topic?


Explain the mechanisms of thermal energy transfer: conduction and convection in terms of particles; and radiation in terms of emission and absorption of infra-red electromagnetic waves; all in the context of a domestic hot-water system

 

Use the Zeroth Law of Thermodynamics to explain thermal energy transfer within a domestic hot water system

 

Describe how a domestic hot water heating system works and is controlled and explain how the processes of heat transfer are used to maximise it's effectiveness

 

Explain the limits to the efficiency of energy transfer in a domestic setting


How long will this topic take to study?


On average you’ll be looking at about 4 hours. This includes taught time and independent study.


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