見圖，共八種
1 就效能最好, 5 係最差
(Source: EMSD)
2020年5月9日星期六
2020年5月7日星期四
[AC] 問﹕冷氣機 Window Type, Split Type, VRV 有啲乜分別？
答﹕
Window Type vs Split Type
- 安裝空間考慮，前者要有個窗口窿向街，唔同冷氣機廠商，唔同匹數，個窿大細都有機會唔同；後者要裝室外機，仲要用條雪種喉連住；
- Window Type易拆易裝易維修；
- 美觀考慮Split Type好啲；
- 能源效益Split Type更好；
- Cooling capacity Split Type更高；
- Noise方面都係Split Type較好，因為大部機mechanical moving parts 都放咗响室外；
講得清楚啲，應該用一拖一Direction Expansion DX Split Type 同 Variable Refrigerant Volume VRV 比較，因為兩者都算係Split Type
- 前者係室內機同室外機一拖一；後者係一拖N；Split Type 同室外機條接駁最多行20m; VRV行到80m; 明顯VRV靈活及擴展性更高；(不過由於因為係走Refrigerant都唔係冇距離限制；但走Chilled Water的話可以講係冇距離限制)
- VRV 一拖N較節能因為佢啲Refrigerant可以由sensor control Pulse Modulating Valve PMV 去調Refrigerant flow; DX就唔得；
- VRV 由於一拖N，冇咁易停機，兼設計上有diversity；
- VRV 可同時heating and cooling;
[VRV呢個名比大金註冊咗，呢種技術叫VRF]
最後再講講傳統式同變頻式家用冷氣
變頻特點係起動嗰下為咗追到design, 會開到個compressor 130%, 當達到目的後，就會利用變頻調節，長時間使用上，無論節能、舒適度、耐用度都會比傳統好得多。
傳統既係一到某點就熄compressor, 太熱又開返，咁自然compressor損耗大之餘舒適度又冇咁好因為忽冷忽熱。
又由於變頻起動嗰下耗電量特別高，長時間用會著數過傳統式；又或離開一陣，唔熄冷氣仲慳過熄冷氣因為頭嗰段耗電量特別高。
[AC] [EL] [PD] [FS] 問﹕安老院 / 老人院 Residential Care Homes (Elderly Persons) 設計上有乜考慮？
答﹕
PD:
- re-filling pipe connecting to u-trap of floor drain.
- vent pipe outlet for drainage pipe riser will be at roof above parapet wall.
Electrical
Lift:
- lift will be capable to be isolated to one dedicated floor in case that particular floor is designated as isolated floor to reduce contact with other floors
Social Welfare Department 社會褔利署出過一本守則，Code of Practice for Residential Care Homes (Elderly Persons), 亦都有條叫安老院條例 Cap. 459 Residential Care Homes (Elderly Persons) Ordinance;
啲嘢寫到好general, 不外乎FS 161, FS 251, FS 314 / 5014; WR1; Certification for gas installation etc.;
起碼要知有本咁既嘢，有條咁既法例；
How to enhance MEP design against coronavirus-19 in elderly center
MVAC:
- Install air purifier for occupant area
- sufficient separation (greater than 5m) between intake and exhaust louvre
- bathroom(toilet) for each dormitory will have independent ventilation system and direct fresh air intake from window.,ach dormitory is provided with openable window
- low level exhaust will be provided for those public toilets to minimize air contaminants in the breathing zone/ level.
- each dormitory is provided with individual fresh air fan connecting directly from external
MVAC:
- Install air purifier for occupant area
- sufficient separation (greater than 5m) between intake and exhaust louvre
- bathroom(toilet) for each dormitory will have independent ventilation system and direct fresh air intake from window.,ach dormitory is provided with openable window
- low level exhaust will be provided for those public toilets to minimize air contaminants in the breathing zone/ level.
- each dormitory is provided with individual fresh air fan connecting directly from external
- Heating equipment
PD:
- re-filling pipe connecting to u-trap of floor drain.
- vent pipe outlet for drainage pipe riser will be at roof above parapet wall.
Electrical
- Public Address PA system
- Electrical Call Bell
- Water Heater
Lift:
- lift will be capable to be isolated to one dedicated floor in case that particular floor is designated as isolated floor to reduce contact with other floors
FS
- Smoke detection system provide used for sleeping accommodation.
Maintenance:
- sufficient access panels or air cleansing points for air duct cleaning and inspection.
- stop using air-to-air heat recovery system to limit the air transmission risk.
- frequent cleaning/ replacement of air filters, including fresh air fan filter and AC
indoor unit air filter.
- regular cleaning of ventilation duct work.
Maintenance:
- sufficient access panels or air cleansing points for air duct cleaning and inspection.
- stop using air-to-air heat recovery system to limit the air transmission risk.
- frequent cleaning/ replacement of air filters, including fresh air fan filter and AC
indoor unit air filter.
- regular cleaning of ventilation duct work.
(鳴謝﹕紅豆、諾克Sir；Source: https://www.swd.gov.hk/storage/asset/section/2923/tc/CoP_RCHE_Chi_20200101.pdf )
[AC] [EL] [FS] [PD] 問﹕垃圾及物料回收房及垃圾槽 Refuse Storage and Material Recovery Chambers and Refuse Chutes 設計上有啲乜考慮？
答﹕
According to App-35 & Cap. 123, Section 38:
[AC] [EL] [FS] [PD]
-AC: Centralised ventilation 的話， air purifier before final discharge; or mechanical fan + particulate if no particular odour;
-AC: 如果係 centralised ventilation system, exhaust 要放upper roof; 但如果周圍被高樓包住，discharge就放返响RS&MRC;
- AC: RS&MRC房裡面要有air purifying devices, e.g. Chemical air scrubber, bio-oxygen generator, photo-oxidation generator etc.;
- at least 3 ACH;
- DR: min. 100mm pipe to Back Inlet Trapped Gully BITG;
- PL: Water supply point;
- FS: Sprinkler, Fire Alarm
- EL: min. 120 lux;
-乎合Noise Control Ordinance (Cap 400);
- Refuse chutes should be vertical;
[MISC]
成間嘢個大細有規管, from BD App-35
(Source: Cap. 123, Section 38)
2020年5月6日星期三
[AC] 問﹕Fan 有啲乜種類？各有乜特別？
答﹕
Axial Fan and Centrifugal Fan
Axial Fan入風同出風係同一個方向；flow rate大但 pressure 細，通常會用响啲大面積散熱地方如dry cooler; input power 都相對低啲；
Centriufugal Fan 入風同出風係成九十度；flow rate 同 pressure都可以去到好大；high pressure drop e.g. air duct 嗰啲會用到；
[EL] 問﹕摩打 Motor 分別有幾多種？各有啲乜特點？
答﹕
簡單地用三種比較﹕
1. Synchronous Motor 同步電機 vs Induction Motor 異步電機；
2. Single Phase vs Three Phase;
3. Induction Motor (Squirrel-Cage Rotor) vs Induction Motor (Slip Ring Rotor) ；
1. Synchronous Motor 同步電機 vs Induction Motor 異步電機；
Synchronous Motor 個 rotor係 D.C.經由 slip ring比，個rotor就好似一舊永久磁鐵, Stator rotating magnetic field;
兩者最大分別係Synchronous Motor 加 load 只要唔過個limit, 個轉速都唔會改變；有slip ring, non self started (要D.C.+A.C.), 個lagging or leading can be operated, Efficiency 高啲但又貴啲；响啲需要轉速精準既場合會用到。
Induction Motor 係最大路，直接隊電入個Stator後個magnetic field不斷咁轉變就可以啟動個motor, 唔洗任何多餘起動，brush嗰堆嘢通通都唔洗要；個速度好容易通過改變frequency嚟調較；個load increase 個speed會decrease;
更詳盡可參考呢條Youtube:
Synchronous Motor: https://www.youtube.com/watch?v=Vk2jDXxZIhs
Induction Motor: https://www.youtube.com/watch?v=AQqyGNOP_3o
2. Single Phase vs Three Phase;
Single Phase 會揹一隻capacitor 嚟啟動，個功率低啲，會用响風扇、電櫃等家電；
Thress Phase 功率大啲會用响compressor etc.;
更詳盡可參考呢條Youtube:
Single Phase: https://www.youtube.com/watch?v=awrUxv7B-a8
3. Induction Motor (Squirrel-Cage Rotor) vs Induction Motor (Slip Ring Rotor) :
最大分別係後者起動個Torque大啲但電流又細啲，加速起嚟順啲，Speed Control做得好啲；
但複雜咗，即係貴咗之餘又難維修啲。
Slip Ring 主要會用响 lift, crane, hoist machine
更詳盡可參考呢條Youtube: https://www.youtube.com/watch?v=JPn5Ou-N0b0
再補充下直流Motor, 一般Building Services上都唔會用到，係以前玩啲四驅車之類會用得多，得個知字。
特點係用直流比電(廢話)，有個brush, 意味住有損耗；
可以响個Rotor加多幾loop嚟令佢轉速更穩定，以前啲四驅車摩打係三loop
亦可以用組線嚟取代舊永久磁鐵，有兩種駁法，一種係Series, 一種係Shunt
Series特徵係一開始個Torque夠大，但一加Torque的話個Speed會drop得好快
Shunt就係一開始個Torque唔大，但加load都話個speed drop得冇咁快
更詳盡可參考呢條Youtube: https://www.youtube.com/watch?v=LAtPHANEfQo
(Source: Learn Engineering https://www.youtube.com/channel/UCqZQJ4600a9wIfMPbYc60OQ)
2020年5月5日星期二
[AC] [EL] 問﹕Retro Commissioning 係乜嚟？同BEEO / BEC 有啲乜分別？
答﹕
背景﹕由於香港九成用電係嚟自building, 舊樓好多BS系統效能唔高。
Retro Commissioning 係重新校驗BS系統，一棟樓行得耐既時候，好多時個control system又outdate, 啲sensor又唔準等等，一旦較正咗個building owner即時慳到電有著數；主要係一個systematic process quick fix operational improvements save energy而唔係成件equipment咁換；
而BEEO / BEC 係針對New Building or Major Retrofitting Works, 而且十年要一次Energy Aduit;
*Major Retrofitting Works MRW 定義﹕
- 換BS嘢既面積大過500 m2;
- 換個electrical circuit 大過400A;
- 換AC嘢大過350kW;
- 換lift;
EMSD出咗本Technical Guidelines on Retro-Commissioning, 本嘢有三個主要部份
1. Work Stage: Planning-->Investigation-->Implementation-->On-going
2. Example;
3. Check List;
Stage 1: Drawings manual collection, inspection, develop plan;
Stage 2: Site survey, conduct data logging, monitoring, identify potential measures;
Stage 3: Performing verification, training O&M staff;
Stage 4: Electricity bill, satisfaction of occupants, continuous monitoring;
Example:
現在﹕總共有三台Air Cooled Chillers 行VSD，平時30-50% load嗰陣係行兩台。
新方案﹕回顧返個cooling load profile後，會唔會响30-50% load嗰陣同時行三台COP仲好啲？因為用VSD的話响part load condition個綜合COP更高。
結果﹕果然好咗喎。完。
(Source: EMSD)
背景﹕由於香港九成用電係嚟自building, 舊樓好多BS系統效能唔高。
Retro Commissioning 係重新校驗BS系統，一棟樓行得耐既時候，好多時個control system又outdate, 啲sensor又唔準等等，一旦較正咗個building owner即時慳到電有著數；主要係一個systematic process quick fix operational improvements save energy而唔係成件equipment咁換；
而BEEO / BEC 係針對New Building or Major Retrofitting Works, 而且十年要一次Energy Aduit;
*Major Retrofitting Works MRW 定義﹕
- 換BS嘢既面積大過500 m2;
- 換個electrical circuit 大過400A;
- 換AC嘢大過350kW;
- 換lift;
EMSD出咗本Technical Guidelines on Retro-Commissioning, 本嘢有三個主要部份
1. Work Stage: Planning-->Investigation-->Implementation-->On-going
2. Example;
3. Check List;
Stage 1: Drawings manual collection, inspection, develop plan;
Stage 2: Site survey, conduct data logging, monitoring, identify potential measures;
Stage 3: Performing verification, training O&M staff;
Stage 4: Electricity bill, satisfaction of occupants, continuous monitoring;
現在﹕總共有三台Air Cooled Chillers 行VSD，平時30-50% load嗰陣係行兩台。
新方案﹕回顧返個cooling load profile後，會唔會响30-50% load嗰陣同時行三台COP仲好啲？因為用VSD的話响part load condition個綜合COP更高。
結果﹕果然好咗喎。完。
(Source: EMSD)
2020年5月4日星期一
[AC] [PD] [EL] 問﹕Swimming Pool 泳池 BS Design 有啲乜要考慮？
答﹕
Indoor Design: 30°C D.B., 60% R.H., Slightly Negative Pressure; Low exhaust; 4-6 ACH; 派風要平均；
Reason:
- 30°C D.B. reduce operating cost; 雖然更容易condense (平時可能16°C, 但而家22°C就condense), 但送風溫度可以增加，減低energy consumption;
- 60% R.H. 係响comfort同energy consumption之間攞個平衡，再高啲人唔舒適，低啲就嘥電；仲有如果濕度太高會growth of mold and fungi;
- Negative pressure 係為咗避免啲水氣到處走，因為泳池既水氣有Chloramine, 會腐融建築物；
- Low Exhaust near the surface of the pool assist evaculating chloramine;
- 派風唔平均會局部condense;
此外，Cooling Loading Estimation 嗰陣都要留意個pool evaporation rate, ASHRAE有講點計，池水溫度越高evaporation rate 越高；仲有一系列方法可以用少啲Chloramine, 如Ozonation, UV 消毒殺菌、加大個water exchange rate etc.
响香港，泳池係要根據Swimming Pool Regulation Cap. 132, Section 42向食環署Food and Environmental Hygiene Department FEHD攞牌照，機電方面大概係包括
- 有水入面既泳池燈的話，25V內；
(Source: 2019 ASHRAE Handbook Applicaiton; Swimming Pool Regulation Cap. 132, Section 42)
Indoor Design: 30°C D.B., 60% R.H., Slightly Negative Pressure; Low exhaust; 4-6 ACH; 派風要平均；
Reason:
- 30°C D.B. reduce operating cost; 雖然更容易condense (平時可能16°C, 但而家22°C就condense), 但送風溫度可以增加，減低energy consumption;
- Negative pressure 係為咗避免啲水氣到處走，因為泳池既水氣有Chloramine, 會腐融建築物；
- Low Exhaust near the surface of the pool assist evaculating chloramine;
- 派風唔平均會局部condense;
- 有水入面既泳池燈的話，25V內；
- 泳池所有地方包括水面要有200lux及一個鐘後備電;
- 有蓋池四個鐘換水一次；露天六個鐘一次；每年最少成個池抽乾一次；
ASD都有一本專係Swimming Pool Water Treatment General Specfication
Filtration Plant Example, 啲泳池水係會經Sand Filter, Chemical, 再過Heat Pump / Heater (如有需要)。
- 有蓋池四個鐘換水一次；露天六個鐘一次；每年最少成個池抽乾一次；
ASD都有一本專係Swimming Pool Water Treatment General Specfication
Filtration Plant Example, 啲泳池水係會經Sand Filter, Chemical, 再過Heat Pump / Heater (如有需要)。
2020年5月3日星期日
[Contract] 問﹕香港 Building 有邊幾種Contract係常用？有啲乜特點？
答﹕
講之前先搞清Bills of Quantities BQ 同 Schedule of Rates SoR分別﹕
- BQ係將Drawings+Spec.裡面嘅嘢清清楚楚Items連數量列晒出嚟，會form part of contract;
- SoR淨係將啲Rate列出嚟，但冇個量；就算佢好人整埋比你都好，個數量都只係比你參考，而唔會form part of contract;
做 Building 最常用，應該係
- Lump Sum Contract with Drawings and Specification
個tenderer只會收到圖同spec.唔會有BQ，跟住就自己跟圖估一個總價，承諾呢個價搞掂啲嘢；相對細型嘅project或E&M contract會用到，如果係大型project用的話風險相對較高；
- Lump Sum Contract with firm BQ
同上類似，但個BQ係Architect/Engineer/QS比埋你；個BQ可能會用"provisional quantities"包埋一啲出標前未有design detail嘅嘢，或用"provisional sums"包一啲出標前未design嘅嘢；總之就係盡量確保返標個價係包得齊晒所有要做嘅嘢；對報標者最大好處係慳返數數量時間，唔洗揹數錯嘅風險
- Design and Build Contract
Tenderer包Design, Construction, contract 用一個總價去批出；
講之前先搞清Bills of Quantities BQ 同 Schedule of Rates SoR分別﹕
- BQ係將Drawings+Spec.裡面嘅嘢清清楚楚Items連數量列晒出嚟，會form part of contract;
- SoR淨係將啲Rate列出嚟，但冇個量；就算佢好人整埋比你都好，個數量都只係比你參考，而唔會form part of contract;
做 Building 最常用，應該係
- Lump Sum Contract with Drawings and Specification
個tenderer只會收到圖同spec.唔會有BQ，跟住就自己跟圖估一個總價，承諾呢個價搞掂啲嘢；相對細型嘅project或E&M contract會用到，如果係大型project用的話風險相對較高；
- Lump Sum Contract with firm BQ
同上類似，但個BQ係Architect/Engineer/QS比埋你；個BQ可能會用"provisional quantities"包埋一啲出標前未有design detail嘅嘢，或用"provisional sums"包一啲出標前未design嘅嘢；總之就係盡量確保返標個價係包得齊晒所有要做嘅嘢；對報標者最大好處係慳返數數量時間，唔洗揹數錯嘅風險
- Design and Build Contract
Tenderer包Design, Construction, contract 用一個總價去批出；
Traditional Contract 同 Design and Build Contract 最大分別係前者將價就貨，後者將貨就價。
舉一例，你想炒一碟蝦仁蛋飯，Traditional Contract 係寫清楚點嘢要點炒法，要用啲乜料。出咗標後，如果忽然想將蝦改做龍蝦，一樣改得，加錢就得。雖然改下改下好易超支，但件貨質量就有保障。
Design and Build Contract 就連碟嘢點炒要用乜料都唔洗諗，直接出標叫人整碟嘢就得。但出咗標後，人地實會搵啲最平嘅料同最慳氣慳力嘅方法同你炒，件貨質量實唔多好；同埋如果出標後忽然想改設計，條數就冇Traditional Contract咁易計。Design and build對於純功能性嘅項目如工廠大廈會較好，但如果係有好多architectural input嘅樓如office, 住宅等就冇咁好，因為仲有個問題係無論出個design brief也好，contractor做design返標，及tender assessment等嘅時間都會長唔少。
如果係某啲specicalist, e.g. lift, security etc., 都有可能係用個別嘅design and build合約，再將其包入main contract。
- Construction Management Contract
簡單嚟講即係業主借大判嘅人頭去做項目管理，至於最終單project賺蝕好，唔關個大判事，佢地只收人頭費。
- Remeasurement Contract containing BQ
一般civil projects會用到，個Tenderer楂住個BQ (可能係provisional quantities, 一個大約嘅數量) 乘收費率就攞到總投標價，但做完後會再實地量度一次嚟決定點找數；
- Remeasurement Contract containing SoR
同上類似，但個量就落標嗰陣估唔到，响啲經常性或維修工程會用到；
- Cost Reimbursement Contract
Contractor 嘅實際成本再加利潤嚟找數，穩賺冇賠，一般會用响啲緊急工程度；
Build - Operate - Transfer BOT
- 例子就係起隧道咁，由方案、設計、建造、營運等全部交晒比個contractor，跟住佢地有廿年經營權，之後交返比政府；
Tender Stage 包括﹕
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- Remeasurement Contract containing BQ
一般civil projects會用到，個Tenderer楂住個BQ (可能係provisional quantities, 一個大約嘅數量) 乘收費率就攞到總投標價，但做完後會再實地量度一次嚟決定點找數；
- Remeasurement Contract containing SoR
同上類似，但個量就落標嗰陣估唔到，响啲經常性或維修工程會用到；
- Cost Reimbursement Contract
Contractor 嘅實際成本再加利潤嚟找數，穩賺冇賠，一般會用响啲緊急工程度；
Build - Operate - Transfer BOT
- 例子就係起隧道咁，由方案、設計、建造、營運等全部交晒比個contractor，跟住佢地有廿年經營權，之後交返比政府；
Tender Stage 包括﹕
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如果係做public works的話，發展局有張list限制邊啲contractor先可以落標；Group A只可承擔低於1.5億、Group B低於4億、Group C高於4億。可以去發展局嘅網頁參考﹕https://www.devb.gov.hk/en/construction_sector_matters/contractors/contractor/index.html
再以BS為例，例如做FS installation, 就要响發展局"認可公共工程物料供應商及專門承造商名冊 The List of Approved Suppliers of Materials and Specialist Contractors for Public Works"入面度搵fs contractor, 當中又分group or class, 可以到"工程類別、級別及組別說明 Category, Class and Group Description"入面度睇佢地嘅定義，就以消防工程為例，係分咗Group I or II. Group I的話只可承包460萬以下嘅合約，而Group II就冇限制。
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話說CIC 2019年出版關於工程合約嘅參考文件 Reference Material on Selection of Contractors 寫得幾清晰，值得一讀。
2020年5月2日星期六
[EL] 問﹕BEC / BEEO 2018 Lift / Escalator / Passenger Conveyor Installation 有啲乜要點？
答﹕
- Max. allowable power: For lift, 對表，Rated load & speed 唔能夠大過某個kW;
- Max. allowable lift decoration load: Rated load 細過1800kg or 大過1800kg 兩種計法；
- Lift parking mode: During low traffic, at least 1 lift not respond to passenger call until return to normal operation mode;
- Ventilation / AC: 部Lift 冇人用要識得自己熄，有人用先自己著返；
- Regenerative Braking: 部Lift rated load 大過1000kg & 2.5m/s 就要有；
- 其他如LPD, THD, P.F., Energy monitor etc. 同Electrical 嗰 part 類似；
- Also refer: https://elvissharing.blogspot.com/2020/03/el-lift-elevator.html
- Max. allowable power: For lift, 對表，Rated load & speed 唔能夠大過某個kW;
- Max. allowable lift decoration load: Rated load 細過1800kg or 大過1800kg 兩種計法；
- Lift parking mode: During low traffic, at least 1 lift not respond to passenger call until return to normal operation mode;
- Ventilation / AC: 部Lift 冇人用要識得自己熄，有人用先自己著返；
- Regenerative Braking: 部Lift rated load 大過1000kg & 2.5m/s 就要有；
- 其他如LPD, THD, P.F., Energy monitor etc. 同Electrical 嗰 part 類似；
- Also refer: https://elvissharing.blogspot.com/2020/03/el-lift-elevator.html
[EL] 問﹕BEC / BEEO 2018 Electrical Installation 有啲乜要點？
答﹕
- Transformer efficiency: above 99%;
-Max. allowable copper loss for Main circuit, Feeder Circuit, Sub-main Circuit and Final Circuit;
-Max. allowable copper loss for Main circuit, Feeder Circuit, Sub-main Circuit and Final Circuit;
- Main circuit (Tx to LV switch board) 0.5%;
- Feeder (LV switch board to equipment) 2.5%;
- Sub main circuit (LV switch board to local distrubution board) 矮過100m 1.5%; 高過100m 2.5%;
- Final circuit (Local distrubution board to equipment) 1%;
- Balancing of single phase loads: 3 phase 4 wire circuits 大過400A 而又有 1 phase load 的話，max unbalanced single phase loads 要少過10%;
- Min. allowable total Power Factor: 大過400A的話，要細過 0.85;
-Max. allowable total Harmonic Distortion: Harmonic Distortion in % of Designed Circuit Current 受限，Designed Circuit Current 越大，允許既% 越細 (同copper loss 一樣有公式計)；
- Metering and Monitoring in above circuit for energy aduit;
- Min allowable motor efficiency, 2-pole (單相) and 4-pole (三相) , motor rated output 越大，所以要既efficiency 越高；
[EL] 問﹕BEC / BEEO 2018 Lighting Installation 有啲乜要點？
答﹕
最大亮點首選係Lighting Power Density LPD (W/m2) 要求，要留意係，呢個要求係Watt per meter Square, 而唔係CIBSE Guide既 Lux requirement
其次係Minimu Number of Lighting Control Points for Office
仲有一堆Automatic Lighting Control requirements
also refer: https://elvissharing.blogspot.com/2020/03/el.html
最大亮點首選係Lighting Power Density LPD (W/m2) 要求，要留意係，呢個要求係Watt per meter Square, 而唔係CIBSE Guide既 Lux requirement
其次係Minimu Number of Lighting Control Points for Office
仲有一堆Automatic Lighting Control requirements
also refer: https://elvissharing.blogspot.com/2020/03/el.html
[AC] 問﹕BEC / BEEO 2018 Air Conditioning Installation 有啲乜要點？
答﹕
- Indoor / outdoor design condition
Air Side
- Air leakage limit;
- Seperate air distribution for process zone, 即係派比啲特殊Design condition地方如Data Center, 條風候就只可以派比佢，唔可以同其他地方Share, 除非特殊條件如嗰個地方好細/嗰個地方有獨立Control, 唔洗再reheat等；
- CAV max. 1.6W/L/s; VAV 2.1W/L/s; Fan efficiency in specific condition;
- Terminal reheat, 即係凍完又熱 (反之亦然)，除非1. VAV 已調到30%; 2. 細過140L/s; 3. 為咗達到特定humidity level; 4. 75%以上係用re-claim energy;
Water Side
- Minimum Insulation Thickness for Chilled & Refrigerant Pipework;
- Minimum Chiller / Heap Pump COP, refer https://elvissharing.blogspot.com/2020/03/ac-chiller.html ; 350kW以上要有Energy Metering;
- Friction loss of Water Pipe;
- Pump efficiency in specific condition;
- Indoor / outdoor design condition
Air Side
- Air leakage limit;
- Seperate air distribution for process zone, 即係派比啲特殊Design condition地方如Data Center, 條風候就只可以派比佢，唔可以同其他地方Share, 除非特殊條件如嗰個地方好細/嗰個地方有獨立Control, 唔洗再reheat等；
- CAV max. 1.6W/L/s; VAV 2.1W/L/s; Fan efficiency in specific condition;
- Terminal reheat, 即係凍完又熱 (反之亦然)，除非1. VAV 已調到30%; 2. 細過140L/s; 3. 為咗達到特定humidity level; 4. 75%以上係用re-claim energy;
- Minimum Insulation Thickness for Chilled & Refrigerant Pipework;
- Minimum Chiller / Heap Pump COP, refer https://elvissharing.blogspot.com/2020/03/ac-chiller.html ; 350kW以上要有Energy Metering;
- Friction loss of Water Pipe;
- Pump efficiency in specific condition;
2020年4月28日星期二
[AC] 問﹕Refrigerant 主流有邊幾種？選擇時有乜考慮？
答﹕
R407C, R410a, R134a, R123
R22
講下故事，得個知字。已被淘汰，因為Ozone Depletion Potential ODP會破壞大氣臭氣層。其餘介紹嗰啲都唔會有呢個問題。
先以易燃及毒性考慮，ASHRAE有個表
R407C (A1)
混合成份。由於容量同壓力同R22比較接近，所以容易直接取代R22. 但個效能會稍為降低。由於係混合比例緣故一有少少漏就嚴重改變特性，要放盡再充過。中/大型Chiller會用到。亦會用响Heat Pump, 因為Condense 溫度較高，去到六十幾度，用R410a會太高磅，用R134a效能又唔夠。
R410a (A1)
混合成份。容量及壓力都比R22高出唔少，但同時效能都比其高。所以設計上Comprssor等部件會更厚，但又同時可降低噪音。响啲細機如家用冷氣機會用到。
R134a (A1)
單一成份。取代舊有R12. 容量及壓力都比R22低一截，所以機身等部件都要做大啲，相對效能亦冇R22高。但單一純種關係，漏咗唔洗放晒先入，可以逐小咁補，較啱大型機用。
R123 (B1)
效能高，液態唔驚漏，GWP都低。但有微毒性。大型機會用。
到2019年，人類再提高標準，响國際協議Kigali Amendment 對高Global Warming Potential GWP值既Refrigerant都選擇逐步淘汰。 R407C, R410a, R134a都係高GWP系列。
R134a (A1) --> R1233zd (A1) / R513A (A1)
R410a (A1) --> R32 (A2L)
R123 (B1) --> R1234ze (A2L)
其實據FSD同EMSD既文件見到，似乎唔太主張香港港呢啲高密度環境度轉用較易燃既Refrigerant, 所以上面灰咗嗰啲都係得個知字。
(鳴謝﹕K、紅豆；Source: 冷暖在線, https://www.emsd.gov.hk/filemanager/tc/content_767/pms2019-2.pdf)
R407C, R410a, R134a, R123
R22
講下故事，得個知字。已被淘汰，因為Ozone Depletion Potential ODP會破壞大氣臭氣層。其餘介紹嗰啲都唔會有呢個問題。
先以易燃及毒性考慮，ASHRAE有個表
R407C (A1)
混合成份。由於容量同壓力同R22比較接近，所以容易直接取代R22. 但個效能會稍為降低。由於係混合比例緣故一有少少漏就嚴重改變特性，要放盡再充過。中/大型Chiller會用到。亦會用响Heat Pump, 因為Condense 溫度較高，去到六十幾度，用R410a會太高磅，用R134a效能又唔夠。
R410a (A1)
混合成份。容量及壓力都比R22高出唔少，但同時效能都比其高。所以設計上Comprssor等部件會更厚，但又同時可降低噪音。响啲細機如家用冷氣機會用到。
R134a (A1)
單一成份。取代舊有R12. 容量及壓力都比R22低一截，所以機身等部件都要做大啲，相對效能亦冇R22高。但單一純種關係，漏咗唔洗放晒先入，可以逐小咁補，較啱大型機用。
R123 (B1)
效能高，液態唔驚漏，GWP都低。但有微毒性。大型機會用。
到2019年，人類再提高標準，响國際協議Kigali Amendment 對高Global Warming Potential GWP值既Refrigerant都選擇逐步淘汰。 R407C, R410a, R134a都係高GWP系列。
R134a (A1) --> R1233zd (A1) / R513A (A1)
R410a (A1) --> R32 (A2L)
R123 (B1) --> R1234ze (A2L)
其實據FSD同EMSD既文件見到，似乎唔太主張香港港呢啲高密度環境度轉用較易燃既Refrigerant, 所以上面灰咗嗰啲都係得個知字。
(鳴謝﹕K、紅豆；Source: 冷暖在線, https://www.emsd.gov.hk/filemanager/tc/content_767/pms2019-2.pdf)
[AC] [EL] [FS] 問﹕試講講Data Center Design 有啲乜要注意？
答﹕
[AC]
Design Condition:
In General, D.B.: 18℃, R.H.: Less than 60%; 當然亦都要睇件Datacom Equipment環境溫/濕度需求
Data Center 同 Non Data Center 既Chiller分開比，Data Center Area 要N+1 Redundancy;
Gas Purging System要有個手動Exhaust Fan, 因為如果起咗Total Flooding System的話，就要靠呢把Fan嚟清；
計Sensible Load方面，ASHRAE都有比個趨勢估算出嚟，見得出Scientific用既GPU比雲儲存散熱更高；Communication 係最低；
上述係講緊一隻42U櫃既散熱量，42U係咁既樣
1U就即係入一件
有Liquid-Cooled, 呢種玩法就要確保响Dew Point以上防Condense
有Air-Cooled, 通常都係由地板入
Air-Cooled用Computer Room Air Conditioning CRAC Unit
[EL]
詳見 https://elvissharing.blogspot.com/2020/03/el-how-to-plan-design-electricity.html , 都係啲無限備份玩法。
Electrical Busway, 响上面好似電車路軌咁攞電
UPS可能會用有Flywheel嗰種，Wiki話係online方式，養住隻轉緊既飛輪可以頂住30s 等Genset起動， 及見 https://elvissharing.blogspot.com/2020/04/el-uninterruptible-power-supply-ups.html
此外為咗避免EMI Interference, IT cables 走High Level; Power Cable 行Raised Floor;
要因應BEEO裝Digital Power Analyzer 計住電流、電壓、功率 (7.7 Metering & Monitoring Facilities, Main Circuit, Feeder & Sub-main Circuit)
[FS]
Total Flooding System, see https://elvissharing.blogspot.com/2020/04/fs-gaseous-extinguishing-system.html
Very Early Smoke Detection Apparatus, see https://elvissharing.blogspot.com/2020/04/fs-automatic-fire-alarm-system.html , 但留意呢個System係唔會用嚟踢著FM200, 只係為咗早啲知
[MISC]
Water Leakage Detection (Linear Type)
Structured Cabling System
有Copper Cable & Fiber, 兩者各有優勢所以响Data Center度會混合嚟用。放線方式有國際標準或ER要求。
Optical Fiber: 輕、距離遠、速度快；
Copper Cable: 更可靠、响Data Center裡面功率低散熱少耗電少；
Cat5, Cat5e, Cat5 分別
(鳴謝﹕紅豆；Source: 2019 ASHRAE Handbook Application - Chapter 20)
[AC]
Design Condition:
In General, D.B.: 18℃, R.H.: Less than 60%; 當然亦都要睇件Datacom Equipment環境溫/濕度需求
Gas Purging System要有個手動Exhaust Fan, 因為如果起咗Total Flooding System的話，就要靠呢把Fan嚟清；
計Sensible Load方面，ASHRAE都有比個趨勢估算出嚟，見得出Scientific用既GPU比雲儲存散熱更高；Communication 係最低；
1U就即係入一件
有Liquid-Cooled, 呢種玩法就要確保响Dew Point以上防Condense
有Air-Cooled, 通常都係由地板入
Air-Cooled用Computer Room Air Conditioning CRAC Unit
詳見 https://elvissharing.blogspot.com/2020/03/el-how-to-plan-design-electricity.html , 都係啲無限備份玩法。
Electrical Busway, 响上面好似電車路軌咁攞電
UPS可能會用有Flywheel嗰種，Wiki話係online方式，養住隻轉緊既飛輪可以頂住30s 等Genset起動， 及見 https://elvissharing.blogspot.com/2020/04/el-uninterruptible-power-supply-ups.html
要因應BEEO裝Digital Power Analyzer 計住電流、電壓、功率 (7.7 Metering & Monitoring Facilities, Main Circuit, Feeder & Sub-main Circuit)
Total Flooding System, see https://elvissharing.blogspot.com/2020/04/fs-gaseous-extinguishing-system.html
Very Early Smoke Detection Apparatus, see https://elvissharing.blogspot.com/2020/04/fs-automatic-fire-alarm-system.html , 但留意呢個System係唔會用嚟踢著FM200, 只係為咗早啲知
[MISC]
Water Leakage Detection (Linear Type)
Structured Cabling System
有Copper Cable & Fiber, 兩者各有優勢所以响Data Center度會混合嚟用。放線方式有國際標準或ER要求。
Optical Fiber: 輕、距離遠、速度快；
Copper Cable: 更可靠、响Data Center裡面功率低散熱少耗電少；
Cat5, Cat5e, Cat5 分別
2020年4月27日星期一
[Renew./Inno.] 問﹕火神山醫院响工程上有啲乜亮點？
答﹕
响建築Layout上既規劃，令醫護人員逗留既地方及出入通道唔會同病人嗰啲唔會交疊。亦係唔可以隨便徵用酒店/旅館既原因。
應用Design for Manufacturing and Assembly DfMA 及 Modular Integrated Construction MiC (外國有啲叫Prefabricated Prefinished Volumetric Construction PPVC), 詳見 https://elvissharing.blogspot.com/2020/04/renewinno-dfma-prefabrication.html
重點係加大重複構件數量，減少特殊構件數量，咁先容易高效批量生產。
Site Formation 整層HDPE, 再用鋼管墊起，一嚟防水二嚟可以下面走風火水電
逐級負壓系統，見 https://elvissharing.blogspot.com/2020/03/ac-isolation-room-mvac.html
(Source: BIMBOX https://bimbox.top/4914.html)
响建築Layout上既規劃，令醫護人員逗留既地方及出入通道唔會同病人嗰啲唔會交疊。亦係唔可以隨便徵用酒店/旅館既原因。
應用Design for Manufacturing and Assembly DfMA 及 Modular Integrated Construction MiC (外國有啲叫Prefabricated Prefinished Volumetric Construction PPVC), 詳見 https://elvissharing.blogspot.com/2020/04/renewinno-dfma-prefabrication.html
重點係加大重複構件數量，減少特殊構件數量，咁先容易高效批量生產。
Site Formation 整層HDPE, 再用鋼管墊起，一嚟防水二嚟可以下面走風火水電
逐級負壓系統，見 https://elvissharing.blogspot.com/2020/03/ac-isolation-room-mvac.html
(Source: BIMBOX https://bimbox.top/4914.html)
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