(24 Oct) Report 2 – Energy Systems Report Essay

Rep ort 2 E nerg y S yste m s R ep ort

Energ y i n fra str u ctu re o f t h e Z ero C arb on B uild in g

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Name : LAM HONG KI

ID : 18041682

Rep ort 2 E nerg y S yste m s R ep ort – E nerg y i n fra str u ctu re o f t h e Z ero C arb on B uild in g

Content

1. E nerg y o p era tio n o f t h e Z er o -C arb on B uild in g

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2A . P ro d uctio n o f b io d ie se l m ad e f r o m w aste c o ok in g o il

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Mix in g A lc o hol a n d C ata ly st t o s ta rt a C hem ic al R eactio n

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Sep ara tio n

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Rem oval o f A lc o hol

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Bio die se l W ash in g

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2B . S ola r P an el

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The p -n j u nctio n a n d t h e P V e ffe c t

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Multi

– cry sta llin e

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BIP V

– th in f ilm

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Cylin dric al C IG S t h in f il m

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3. U se o f G rid -T ie I n verte r

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Opera tin g p rin cip le

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Safe ty

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4. C om bin ed H ea t a n d P ow er ( C H P) P er fo rm an ce a n d L im it a tio n

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5. Y ou r s it e v is it s h ou ld y ie ld r esu lt s f r o m a f lu e g as a n aly sis f r o m c o m bu stio n p ro cess f o r t h e

tr i

– gen era tio n p ro cess. D esc rib e t h e m eth od o f c o m bu stio n a n d a n aly sis t h e c o m bustio n

co n dit io n s r efe rrin g t o : a ir s u pply , c o m bu stio n e ffic ie n cy , f u el/ a ir r a tio , e tc . J u stif y a n y

assu m ptio n s, d is c u ss y ou r r e su lt s a n d c o m men t o n t h e m eth od olo gy.

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6. A ctiv e S yste m i n Z C B – R eg en era tiv e l i f t s y ste m

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Str e n gth

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Weak ness

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Conclu sio n

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7. P assiv e S yste m i n Z C B – C ro ss-V en tila te d L ayou t

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Str e n gth

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Weak ness

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Conclu sio n

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Rep ort 2 E nerg y S yste m s R ep ort – E nerg y i n fra str u ctu re o f t h e Z ero C arb on B uild in g

1. Energy operation of the Zero-Carbon Building

Various power source are supplying the ZCB, the main power sources are the Town Power

Grid and the Biodiesel Tri-Generator as both of the power source can provide stable power to

the Building, rest of them are various type of PV panel and the Lift’s Regenerative Converter,

these are not stable power source as PV panel is not operable at night, while the Regenerative

Converter cannot run when the Life is idle.

All power source then connect to a Distribution Panel which combine and divert electricity to

the HVAC System and the ELV System in the ZCB.

For the HVAC System, with the advantage of Tri-Generator, Absorption Chiller can be used,

the Hot Water Generated by the generator supplies to the Absorption Chiller and Desiccant

Dehumidifier, while the Absorption Chiller provides Chilled Water to the Desiccant

Dehumidifier, which provides addition Cool Air to the AHU. In the other side, normal

electrical chillers provides Chilled Water to Desiccant Dehumidifier and AHU to support the

operation, AHU then cool the air for the ZCB.

In addition, a Solar Thermal Hot Water System is installed at the roof of the ZCB Cafe to

provide extra hot water.

Furthermore, although the Tri-Generator can provide Exhausted Heat to heat up the building,

consider the weather condition in Hong Kong, the heat is not used efficiently.

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Rep ort 2 E nerg y S yste m s R ep ort – E nerg y i n fra str u ctu re o f t h e Z ero C arb on B uild in g

2A. Production of biodiesel made from waste cooking oil

Mixing Alcohol and Catalyst to start a Chemical Reaction

Biodiesel is produced by reacting the cooking oil with various alcohol chemicals such as

methanol, with catalyst to start the reaction process. due to alcohol can easily vaporize, this

process is done in a enclosed container to prevent the loss of alcohol. To ensure efficiency,

the alcohol should be control near the boiling point to speed up the reaction.

Separation

Glycerol and biodiesel will form after the reaction, with some excess alcohol in it which can

be reuse in another chemical reaction, a separation process is required to separate Glycerol,

Biodiesel and Alcohol. Due to the characteristic of each substance, the glycerol is denser than

the biodiesel, so glycerol will sink to the bottom, in this case, by using a settling vessel, both

substance can be drawn off at the top and bottom.

Removal of Alcohol

Excess Alcohol remains in both Glycerol and biodiesel, to remove the Alcohol in both

substance, this process is commonly done by distillation, the Alcohol then recover to use for

another chemical reaction.

Biodiesel Washing

The Biodiesel produce by the

chemical reaction is not completely

pure Biodiesel, there are remaining

some methanol which is unreacted

and it will cause safety risks to the

Biodiesel Engine. To remove the

Impurity from the Biodiesel,

spraying warm water to the

Biodiesel is one of the effective

method, by using water within

40-50 C, the impurity can be wash

away and the Biodiesel is ready to

use.

Figure 2 ?Flow Chart of Biodiesel Production Process

file:///N:/10.11648.j.ijrse.20140305.12.pdf

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Rep ort 2 E nerg y S yste m s R ep ort – E nerg y i n fra str u ctu re o f t h e Z ero C arb on B uild in g

2B. Solar Panel

The p-n junction and the PV effect

The solar panel converse the sunlight energy to electricity, the solar panel is also known as

PV panel as the conversion is done by the pv effect. The basic PV panel consist of two major

compolance, the p-doped silicon and the n-doped silicon, the interface between the two silicon

is called p-n junction.

PV effect is conduct when the sunlight pass through the silicon, the the electrons will excite

and the positive and negative electrons attract each other, resulting a potential difference

between the two type of silicon. By connectings the wire with a load, current is generated and

a circuit is formed to support the external load.

Multi – crystalline

Multi – crystalline is one type of the

solar panel technology, with comparing

with the mono-crystalline type, it has a

slightly lower efficiency, but the tight

spacing of multi-crystalline can cover

the low efficiency, while this type

operates better in a higher temperature,

placing it on the roof is the most

suitable location as the roof usually

absorb the sunlight directly.

?Figure 3 ? Structure of PV Panel (www.pvinsights.com)

BIPV – thin film

BIPV is so thin that it can be integrated into the building structure such as the glass panel or

sidewalls, this kind of design is usually installed on the windows. Owing to the characteristic ?,

th e e ffic ie n cy o f B IP V i s m uch l o w er t h an o th er t y pes o f P V P an el.

Cylindrical CIGS thin film

CIGS is the only flexible film among these types of PV Panel, it’s also the latest technology,

and because of this, the cost of the CIGS is the most expensive as it’s a experimental product.

Since the film is flexible, it’s suitable to install on curve surface.

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Rep ort 2 E nerg y S yste m s R ep ort – E nerg y i n fra str u ctu re o f t h e Z ero C arb on B uild in g

3. Use of Grid-Tie Inverter

To provide a safe and efficient way to feed back electricity produced by tri – generation onto

the regional energy grid, Grid-Tie Inverter is used.

Operating principle

The electricity generated by the Tri-Generator can be feed back onto the grid by installing

Grid-tie Inverter, To inject electricity back to the the energy grid efficiently and safely, the

Grid-tie Inverter must adjust the source to suitable voltage and frequency to inject into the

electrical power grid.

Safety

In some condition such as the regional grid is down, In the United State of America, an

requirement set by NEC that the Grid-tie Inverter can safely isolate the local grid and separate

from the regional grid.

Such action is to ensure the electricity generate in the site will not transfer to the regional grid

which harm the maintenance workers.

Ref:NEC Handbook 2005, Section 705, “Interconnected Electric Power Production Sources,”

Article 705.40 “Loss of Primary Source”

Figure 3, Grid-tie Inverter in the ZCB Building

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Rep ort 2 E nerg y S yste m s R ep ort – E nerg y i n fra str u ctu re o f t h e Z ero C arb on B uild in g

4. Combined Heat and Power (CHP) Performance and Limitation

The CHP unit installed on the site must ensure they have a optimum performance to run in a

efficient way, to optimal CHP performance, various factor are considered, the following

formula was built by LINDO modelling language to solve the optimum performance.

CH = pfc·Fc + pfa·Fa + pep·Ep – pes·Es + rql·Ql

Operating the CHP unit with reference to the boiler’s demand, and remains at a highest output

when the boiler is in use can help optimum the CHP. The CHP should be able to generate heat

at any time to fulfil the operation of the Tri-Generation. Owing to the hot weather in Hong

Kong, heat is not needed at most of the year, heat rejection device should equip to the system.

This also resulting the system to shutdown due to high returning temperature. In addition,

CHP unit is less efficient when it only supplies to small and single-building like the ZCB.

Figure 4, CHP Energy Flow Diagram (Department of Energy & Climate Change, UK)

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Rep ort 2 E nerg y S yste m s R ep ort – E nerg y i n fra str u ctu re o f t h e Z ero C arb on B uild in g

5. Your site visit should yield results from a flue gas analysis from combustion process

for the tri – generation process. Describe the method of combustion and analysis the

combustion conditions referring to: air supply, combustion efficiency, fuel/ air ratio, etc.

Justify any assumptions, discuss your results and comment on the methodology.

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Rep ort 2 E nerg y S yste m s R ep ort – E nerg y i n fra str u ctu re o f t h e Z ero C arb on B uild in g

6. Active System in ZCB – Regenerative lift system

One of the active system in ZCB is the regenerative lift system, the system can generate

electricity when the lift is going up with light passenger load or going down with full

passenger load. The lift will runs upwards and downwards by the help of gravity and using a

regenerative braking system which base on the dynamic braking.

Strength

Research by EMSD stated that comparing with normal lift, regenerative lift can reduce

electricity usage in average of 20%.

However, the regenerative rate depends on the lift operating speed and travel distance, higher

speed and longer distance can generate more energy.

Weakness

The lift located in ZCB only serves three floors (B/F, G/F, M/F), by observation, the lift is

mostly use between G/F and M/F for a upward travel with light passenger load. In this

situation, although the upward operation can generate electricity, the empty downward load

still cost electricity.

Conclusion

In conclusion, For the lift at ZCB which serves short distance with low traffic rate, regenerate

of electricity is possible, but the payback period will be longer comparing with other high-rise

and popular commercial and office building.

[ ? ?]

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Rep ort 2 E nerg y S yste m s R ep ort – E nerg y i n fra str u ctu re o f t h e Z ero C arb on B uild in g

7. Passive System in ZCB – Cross-Ventilated Layout

The ZCB Building have a cross-ventilated layout specifically design for the hot and humid

weather in Hong Kong. The building face southeast to allow more summer breeze to pass

through the building.

Strength

Cross-Ventilation can help the building to keep in a cool temperature as the wind can blow

away the hot air, by natural ventilation, some building can reduce the indoor temperature up

to 2 C. Allow the Air-Condition to produce less cooling to the building. Furthermore, the

wind can bring away the humid air to allow user in the building feel conform.

Weakness

The ZCB located in dense office building area that can block winds get to the building, there’s

still ventilation but it will be less efficiency comparing with a building located in a open area.

The ZCB building is located in the edge of the highrise building area and next to the seaside,

However the road between buildings which act as a wind corridor, is not pointing at the ZCB

windows. In such case, although the wind can be strong, most of the wind is unable to pass

through the building but pass next to it.

Conclusion

Most o f t h e p assiv e s y ste m r e q uir e s a l o ts o f d esig n t o f a cilita te t h e s y ste m r u ns i n a e ffic ie n t w ay .

Reg ard in g t h e c ro ss-v en tila te d l a y out i n Z C B, d esig nin g t h e p assiv e s y ste m s h ould c o nsid er t h e

ch an ge a t t h e n eig hbourh oo d a re a. a s t h e u nfo re se eab le c h an ges t o t h e a re a, p assiv e s y ste m s h ould a ct

as a s u pportin g s y ste m t o t h e b uil d in g.

Figure 3. Area around the ZCB (Google Map)

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Rep ort 2 E nerg y S yste m s R ep ort – E nerg y i n fra str u ctu re o f t h e Z ero C arb on B uild in g

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