|Roofing 19mm thick||42 Kg/m²|
|Damp-Proofing 19mm thick||41 Kg/m²|
|Road & Footpath 19mm thick||44 Kg/m²|
|Bitumen Roofing Felt|
|Mineral Surface Bitumen||3.5 Kg/m²|
|Solid 25mm thick stone aggregate||55 Kg/m²|
|Areated 25mm thick stone aggregate||15 Kg/m²|
|Blockboard 25mm thick||12.5 Kg/m²|
|Solid clay 25mm thick||55 Kg/m²|
|Solid concrete 25mm thick||59 Kg/m²|
|Cast stone||2250 Kg/m³|
|Concrete 50mm thick||120 Kg/m²|
|25mm thick slab||2 – 5 Kg/m²|
|Gypsum panels and partitions|
|Building panels 75mm thick||44 Kg/m²|
|Sheet 2.5mm thick||30 Kg/m²|
|3 mm thick||6 Kg/m²|
|Gypsum. 13mm thick||22 Kg/m²|
|Plastic sheeting corrugated||4.5 Kg/m²|
|Plywood ( per mm thick)||0.7 Kg/m²|
|Reinforced concrete||2400 Kg/m²|
|Cement : sand (1:3) 13 mm thick||30 Kg/m²|
|Cement : sand (1:3) 13 mm thick||30 Kg/m²|
|(Depending upon thickness & source)||(24 – 78) Kg/m³|
|Solid mild steel||7850 Kg/m³|
|Corrugated roofing sheets per mm thick||10 Kg/m²|
|Tarmacadam (25 mm thick)||60 Kg/m²|
|Terrazzo (25 mm thick)||54 Kg/m²|
|Tiling / roof|
|Slabs 25mm thick||15 Kg/m²|
The English Premier League 2020/2021 season came to an end on May 23 2021. Manchester City won the league with games to spare. Manchester United took second position while Liverpool and Chelsea came 3rd and 4th respectively. The top 4 teams qualified for the Champions League.
Fulham, West Bromwich Albion and Sheffield United are relegated.
Arsenal underperformed again this season finishing 8th position. They will not be playing in Europe this season.
Promising Leicester City eventually dropped out of top four on final day of the season to finish fifth. They however qualify for Europa League football along side West Ham United who finished 6th.
Tottenham Hotspur finished 7th and gain Europa Conference League qualification.
Norwich, Watford and Brentford gain promotion to the premier league.
English Premier League Table 2020/2021 Season Final Standings
|6||West Ham United||38||19||8||11||62||47||15||65|
|16||Brighton & Hove Albion||38||9||14||15||40||46||-6||41|
|19||West Bromwich Albion||33||5||11||22||35||76||-41||26|
Chelsea again made history by winning the 2020/2021 champions league. They beat the favorites, Manchester City 1-0 to claim the title for the second time in their history. Kai Havertz scored the only goal of the match from a defense splitting pass by Mason Mount in the 42nd minute. Manchester city tried in the dying moments to equalise but Chelsea held strong.
It was a well deserved victory for Chelsea as they neutralized the attack of Manchester City all game reducing their effort to just one shot at goal. Chelsea should have scored at least one more if they had taking their chances.
Against all odds Chelsea won the champions league beating Atletico, Porto and Real Madrid on their way to glory.
Chelsea Champions League Journey to Kings of Europe
Components that make up a Solar Electric System
There are 3 major components of a solar electric generating system;
- Solar Panels: which produce electrical energy from the sun
- Battery: to store electrical energy produced by the solar panels
- Inverter: converts direct current produced from the battery or solar panels to alternating current required to power your electrical devices.
Note that there are battery-less solar systems too. If you only need electricity only when the sun is shining then you only need a solar panel and inverter. And if your electrical appliance runs on direct current only, then you only need the appropriate amount of solar panel or panels with a direct current voltage regulator installed.
In advanced countries with 24 hour supply of grid electricity, batteryless solar systems are connected to the grid. The overall goal here is to reduce the cost of grid electricity being paid for by the owner of the solar system. Once the solar panels generate enough electric power for the day, the excess is sold off to the grid. A sophisticated device that calculates the energy produced by the solar system and the excess that is sold off is installed with the system.
Solar Panel Sizing
Solar panels are produced in different power output ratings. There are 10 watts solar panels, 20 watts, 30 watts and so on. A standard solar panel is rated at a power output of around 300 watts. In determining the size and number of solar panels you will need, you will first need to find out your total power consumption requirements.
To know the power consumption of your electrical appliances, check under or back of the appliance.
Once you know the total power requirements of your electrical appliances you can then correctly determine the size and number of solar panels required.
Let’s say the total power consumption of all your electrical appliances is say 3000 watts, then this means you will need ten 300 watts solar panels. Assuming not all your electrical appliances are working at the same time then the panel sizing just calculated above will be adequate. Otherwise you may need to add say one more 300 watts. This is because the solar panels are not 100% efficient.
Suitable Battery and Sizing
Big sized batteries suitable for use with a solar electric system produce a direct current of 12V.
Battery capacity is the key factor here. It is the maximum amount of power the battery can store.
Batteries suitable for the solar system are deep cycle. Deep cycle batteries are designed to discharge to almost it’s full capacity without damage. Say 80 to 90% of total capacity.They look like car batteries. Note that most car batteries are not deep cycle.
There are two major types of battery in the market;
- Lead acid battery
- Lithium battery
Lead acid batteries are very common and cheap. Even though lead acid batteries can be designed for deep cycle use, it is advisable you don’t discharge more than 50% of its capacity to extend battery life. It is also advisable to use flooded lead acid batteries rather than seal lead acid batteries. They last longer when properly maintained. Lifespan of lead acid battery is between 1.5 to 2 years
Lithium batteries are true deep cycle but are expensive. They can support discharges of over 90% of their capacities without damage. They can also support recharge cycles of between 1000 – 3000 times lasting 3 to 5 years if properly used.
Battery capacities are usually expressed as Ah (Ampere hours). To express as Wh ( Watt hours) it should be multiplied by the supplying voltage of the battery which is usually 12V ( V stands for volts). Also note that 1kWh ( kWh stands for Kilowatts hour) = 1000Wh.
For instance, a battery rated 300Ah, and multiplied by 12V gives;
300 × 12= 3600Wh or 3.6kWh.
This means that the fully charged battery can deliver a power of 3.6kW consistently for 1 hour.
Referring to the example on solar panel sizing, recall that we sized for 3000W. Since it is reasonable that all electrical appliances can not all be put on at the same time for 24 hours, we can conclude that on the average, a power of 1500W or 1.5kWh is being utilized every hour. Recall that our calculated battery capacity is 3.6kWh. A little consideration will show that if 3.6kWh is divided by 1.5kW ( which is the average power consumption per hour, it means that a single fully charged 3.6kWh battery will power your electrical appliances for ; (3.6÷1.5= 2.4 hours) 2.4 hours or 2.4h, (h stands for hours). So if you want a 24hour supply you divide 24 hours by 2.4 hours which equals 10. This means you will need ten 3.6kWh capacity batteries.
In truth if you are using lead acid batteries you will need much more.
Since it is not safe to discharge above 50% the rated capacity in order not to damage the battery, then ten batteries will run for 12 hours. That is you need 2 × 10 lead acid batteries to run for 24 hours. But if it’s lithium batteries which can support almost full discharge without damage, then near 24 hours supply is possible with the calculated 10 batteries.
In summary of this section, if it’s lead acid battery, then you will have to double the battery size / number to run for the number of hours it has been designed for. If its lithium battery then increase battery size / number by 10-20 %.
It is better to get a much bigger inverter than what is required. For a 3000W power consumption you can go for a 5000W rated inverter. This will give the inverter much headroom to operate safely. Inverters are prone to overheating when loaded near it’s full capacity.
Your solar electric system will not be complete without a backup generator. When the solar power and batteries run out. The back up generator can restore power and at the same time charge the batteries for another cycle of use.
For the generator to last, it should run at 50% its rated capacity. So let’s say all your household electrical appliances are rated 3000W, then get a backup generator of 6000W.
Your laptop battery power rating can be found labelled on the battery. A typical laptop battery rating is as stated below;
11.1V, 5.2Ah, 57Wh.
This means that the battery supplies 11.1 volts, a current of 5.2 Ampere hours and a power of 57 Watts hour.
What does this information really tell? 5.2Ah means the battery can supply a current of 5.2A in one hour before it runs out . Or 57 Watts in one hour before it depletes provided the voltage supplied remains constant.
So let’s say your laptop power rating is 30Watts then on a battery capacity of 57Wh, your laptop will run for( 57Wh÷30W)= 1.9h or almost 2 hours. In reality it may be more or less as a result of several factors.
Both Watts hour( Wh) and Ampere hour( Ah) are measures of battery capacity. However, Wh is more reliable.
A laptop battery is usually made up of small battery cells. These battery cells are similar in shape to AA alkaline batteries but bigger..
Laptop battery usually consists of at least 3 or 4 battery cells arranged in series. To increase the laptop battery capacity, 2 or more sets of 3 or 4 battery cells in series are arranged in parallel.
The smallest laptop batteries I have come across are the 3 cell batteries. That is, consisting of 3 battery cells in series. These types of batteries are usually made for netbooks.
The standard laptop battery is made up of 6 cells. It consists of 2 sets of 3 battery cells in series, connected in parallel.
Similarly, a 9 cell laptop battery consists of 3 sets of 3 battery cells in series, connected in parallel. Of course there are laptop batteries. comprising sets of 4 battery cells in series, connected in parallel.
Laptop battery cells are connected in series and then in parallel to fulfill 2 purposes;
- To meet the voltage rating required for the laptop to operate. This condition is met when the battery cells are connected in series.
- To increase the time the laptop can run on batteries. This condition is met when sets of battery cells in series are connected in parallel.
Decoding laptop battery power ratings
A single battery cell can supply 3.6 or 3.7 volts and a current of over 2Ah. Since in electrical terms, power = current × volts, a battery cell can supply ( 3.6V× 2Ah = 7.2Wh) a power of over 7.2 Wh.
Battery power ratings for your laptop are labelled on the battery.
For example assuming the battery power ratings are;
11.1V, 5.2Ah and 57Wh.
11.1V is the result of three, 3.7V battery cells in series. That is (3.7 + 3.7 +3.7)V= 11.1V. If the battery rating was 10.8V, then it implies that three 3.6V battery are connected in series, that is (3.6+3.6+3.6)V= 10.8.
5.2Ah is the result of two sets of three 3.7V batteries in series, connected in parallel. It means each of the 3.7V battery supplies a current of 2.6Ah. Even though 3cells are in series, the same 2.6Ah flows through the series connection. But because 2 sets of 3 battery cells in series are connected together in parallel, then the current supplied becomes 2× 2.6Ah = 5.2Ah.
From the calculations given above, you will realise that the laptop battery comprises 6 cells. Since power = current × volts, then each battery cell produces ( 2.6Ah×3.7V) = 9.62Wh ( when fully charged)
57Wh is the result of multiplying the power produced by one battery cell by 6.( since there are six cells in the laptop battery).
I.e. 9.62×6= 57.72Wh rounded down to 57Wh by the manufacturers.
Windows Experience Index (WEI) score is a score that states your computer’s hardware performance characteristics and capabilities. WEI score implies how good your PC is at handling various tasks.
The Windows System Assessment Tool (Win SAT) calculates the WEI score. It reports individual scores of the various hardware components of your PC and states the hardware component with the lowest score as your PC’s Window Experience Index Score. For windows 10 PCs it’s on a scale of 1-10.
How to Determine the WEI Scores of Your Windows 10 PC
- Locate the command prompt app, (you can use the search feature), right click and run it as administrator.
- In the command prompt interface, type, winsat formal, as shown and press enter.
- The WinSAT command will run and determine the WEI scores, wait for it to finish, it can take a while.
- When finished it will state total time it took to complete the process.
Close command prompt then navigate to your PC’s main disk storage. In this case, Local Disk (C:), yours may have a different name.
Click on it, then Windows, Performance, Win SAT, Data Store
Inside the data store folder you will see files containing the WEI scores of major hardware components.
For summary of these scores, open the file containing the name formal assessment; Right click and use a browser to open.
You will see the WinSat scores as shown.
The system score of 5.9 is the Windows experience Index Score for the PC tested. It is the same as the hard disk score which is the lowest score of all the hardware components measured.
To get a better presentation of WEI score you can run the PowerShell app. Run it as administrator. At the command prompt, type;
Get-CimInstance Win32_WinSat as shown. The Windows Experience Index score is revealed.
Another way you can do this is through the Performance Monitor app.
In Performance Monitor, expand data collector sets, expand System then click and start System Diagnostics.
Then, expand Reports followed by System, then System Diagnostics.
Under System Diagnostics, click on the report file that bears your computer name.
To the right of the interface expand Hardware Configuration, then Desktop Rating.
Inside Desktop Rating, click the plus sign to the left of Query, then the plus sign next to Returned Objects. The WinSat Scores are revealed.
As stated earlier the score of the least performing hardware is the WEI Score. It is intended to show the particular hardware creating a bottleneck in the system.In this case the Hard Disk Drive. Replacing with a Solid State Drive (SSD) will improve WEI score.