MEP Technical information

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Cooling tower- *Purpose*: dissipate heat- *Types*: induced draft, forced draft- *Key parts*: fan, fill, basinEfficiency ...
26/04/2026

Cooling tower

- *Purpose*: dissipate heat
- *Types*: induced draft, forced draft
- *Key parts*: fan, fill, basin

Efficiency and water treatment matter

You designing or troubleshooting?

DPS switch
29/01/2026

DPS switch

Here is the complete working of the split air-conditioning system.1 Air from the room enters the indoor unit Warm air fr...
22/01/2026

Here is the complete working of the split air-conditioning system.

1 Air from the room enters the indoor unit Warm air from the room is pulled into the AC through the air filter.

The filter cleans dust and dirt from the air.

2 Ev***rator coil absorbs heat

The cleaned air passes over the ev***rator coil. Inside this coil, cold refrigerant flows and absorbs heat from the room air.

Because heat is removed, the air becomes cool.

3 Cool air is sent back to the room

A fan blows this cooled air back into the room through the louvers.

At the same time, moisture from the air turns into water and collects in the drain pan.

4 Refrigerant moves to the outdoor unit

After absorbing heat, the refrigerant becomes a warm gas and travels through the suction line to the outdoor unit.

5 Compressor increases pressure

The compressor compresses the refrigerant gas. This makes it very hot and high-pressure.

6 Heat is released outside

The hot refrigerant passes through the condenser (heat exchanger). Here, the heat is released to the outside air (or water in water-cooled systems). The refrigerant changes back into a liquid.

7 Expansion valve cools the refrigerant

The liquid refrigerant passes through the expansion valve.

Duct Sweating in HVAC - What We Actually Face on SiteDuct sweating is not a design-calculation problem.It is something m...
22/01/2026

Duct Sweating in HVAC - What We Actually Face on Site

Duct sweating is not a design-calculation problem.

It is something most HVAC engineers face during commissioning and operation, especially in high-humidity and pharma environments.

I've personally seen ducts that looked perfect on drawings, yet water was dripping on site within days of operation.

So what actually goes wrong?

What Really Causes Duct Sweating (Actual Site Scenarios)

1 Insulation looks OK, but ex*****on is poor

On paper, insulation thickness is correct.

On site:

Gaps at joints

Crushed insulation

Damaged v***r barrier

Even small gaps are enough to start condensation.

2 Air leakage at joints, flanges & access doors

This is one of the most common site issues.

Cold supply air leaks out

Duct outer surface cools locally →

Condensation starts exactly at leakage points.

That's why sweating is often seen:

Near flanges

At inspection doors


This content info was from LinkedIn. Credit to the owner info. HVAC system

why use belt spa spb pulley You use SPA and SPB V-belt pulleys for reliable, compact, and efficient power transmission i...
22/01/2026

why use belt spa spb pulley

You use SPA and SPB V-belt pulleys for reliable, compact, and efficient power transmission in machinery, offering higher power capacity than older standard belts (like A/B/C sections) by using deeper, narrower wedge shapes (SPA, SPB) that grip better, reducing slippage and enabling smaller drive centers for a more compact design, suitable for everything from pumps and compressors (SPA) to heavier industrial uses (SPB).

Key Benefits of SPA & SPB Pulleys

Higher Power Capacity: They can transmit more power for their size compared to older belt types, says Naismith Engineering.

Compact Drives: Their design allows for smaller center distances, making drives more compact.

Efficient & Reliable: They offer high efficiency, quiet operation, and are resistant to slipping and misalignment.

Durability: Often made from strong cast iron with protective finishes for resistance to external factors.

SPA vs. SPB (And SPZ/SPC)
These are part of a series (SPZ, SPA, SPB, SPC) that increases in size and power, notes V-Belt Supply.
SPZ: Light-duty (e.g., home appliances , small capacity ahu).
SPA: Medium-duty (e.g., compressors, pumps,AHU Motor).
SPB: Heavy-duty (e.g., agricultural machinery, large pumps).
SPC: Very heavy-duty (e.g., large mills, compressors).

FAHU UNIT eliminatorThe term "FAHU eliminator" most likely refers to the droplet or mist eliminator component within a F...
11/01/2026

FAHU UNIT eliminator

The term "FAHU eliminator" most likely refers to the droplet or mist eliminator component within a Fresh Air Handling Unit (FAHU).

Fresh Air Handling Unit (FAHU)
A Fresh Air Handling Unit (FAHU) is a specialized type of HVAC (Heating, Ventilation, and Air Conditioning) system that conditions and distributes 100% fresh outdoor air into a building. Unlike standard Air Handling Units (AHUs), which often mix return air with fresh air, FAHUs are dedicated to ensuring high indoor air quality by providing a constant flow of treated, pure outdoor air. They are essential in environments requiring stringent ventilation and hygiene standards, such as hospitals, commercial buildings, and industrial facilities.
Key functions of a FAHU include:

Air Filtration: Removing dust, pollutants, pollen, and other contaminants from the incoming air.

Temperature Control: Using cooling or heating coils to adjust the air temperature.

Humidity Control: Maintaining comfortable moisture levels, which may involve dehumidification systems.

Energy Recovery: Utilizing heat recovery systems (like heat wheels or plate heat exchangers) to improve efficiency.

Droplet/Mist Eliminator
The "eliminator" is a critical internal component, typically located after the cooling coils.
Purpose: The primary function of a water or mist eliminator is to prevent liquid water droplets, which condense on the cooling coils, from being carried over into the ductwork and the occupied spaces. This protects downstream equipment, prevents mold growth, and maintains the system's efficiency.

Mechanism:
It uses a series of specially designed plastic or aluminum vanes/blades that force the air to change direction sharply. Due to inertia, water droplets cannot follow the sudden change and are captured on the eliminator's surfaces, where they coalesce and drain away.

In summary, the "FAHU eliminator" refers to the part of the Fresh Air Handling Unit that removes excess moisture from the air stream after the cooling process.

24/12/2025

Keep an eye on learning and knowing
hvac system Heat Load Calculation

Formula:
Q = Area (sqft) × Heat Load Factor (BTU/hr per sqft)

Example:
For a 500 sqft office:
Q = 500 × 30 = 15,000 BTU/hr

To convert to TR (Tons of Refrigeration):
TR = 15,000 ÷ 12,000 = 1.25 TR

🧠 Meaning:
This tells how much cooling capacity (heat load) is required for a given area.
Approximate factor:

30 BTU/hr per sqft → Office

20 BTU/hr per sqft → Residential

---

CFM Calculation (Air Quantity)

Formula:
CFM = Sensible Heat (BTU/hr) ÷ (1.08 × ΔT)

Example:
12,000 BTU/hr ÷ (1.08 × 20°F) = 556 CFM

🧠 Meaning:
CFM (Cubic Feet per Minute) = airflow required to remove the sensible heat.
ΔT = Temperature difference between supply and return air.

---
AHU / FCU Sizing

Rule:
1 TR = 400 CFM
Therefore:
2 TR = 800 CFM
3 TR = 1200 CFM

🧠 Meaning:
To size the Air Handling Unit or Fan Coil Unit airflow based on cooling capacity.
Chilled Water Flow Rate

Formula:
GPM = BTU/hr ÷ (500 × ΔT)

Example:
24,000 BTU/hr ÷ (500 × 10°F) = 4.8 GPM

🧠 Meaning:
Determines chilled water flow for cooling coil or chiller.
ΔT = water temperature difference (supply-return).

---
Flow per Ton

Rule:
1 TR → 2.4 GPM (chilled water)

🧠 Meaning:
Helps in coil and pump sizing.
For 10 TR system → 10 × 2.4 = 24 GPM

---
Chiller Sizing

Formula:
1 TR = 12,000 BTU/hr

Example:
60,000 BTU/hr → 60,000 ÷ 12,000 = 5 TR

🧠 Meaning:
Basic conversion between heat load and chiller capacity.

---
Cooling Tower Sizing

Rule:
Heat Rejection = 1.25 × Load

Example:
If load = 100 TR → Tower capacity = 125 TR

🧠 Meaning:
Cooling tower rejects ~25% extra heat (compressor + inefficiency losses).

---
Pump Head Calculation

Formula:
Power (kW) = (Flow × Head) ÷ (Efficiency × 102)

Example:
Flow = 6 L/s, Head = 27 m, Efficiency = 0.75
Power = (6 × 27) ÷ (0.75 × 102) = 2.12 kW

🧠 Meaning:
Used to select the pump motor size for chilled or condenser water circuit.

---
Fresh Air Requirement

Rule:
Office → 15–25 CFM per person
Example: 20 people → 20 × 15 = 300 CFM

🧠 Meaning:
To maintain oxygen level and indoor air quality.

---
Electrical Load

Rule of Thumb:
1 TR = 1.2–1.4 kW

🧠 Meaning:
Used to estimate total electrical power demand for cooling system.

---
Condenser Water Flow

Rule:
3 GPM per TR

🧠 Meaning:
Standard for water-cooled chillers (higher flow for condenser side).

---
Return Air Duct Sizing

Rule:
2 sqft per TR (approx.)

Example:
For 650 CFM → 650 ÷ 1200 × 1.5 ≈ 1.5–2 sqft

🧠 Meaning:
Return duct size is larger since air velocity is lower to reduce noise.

---
VRV / VRF Capacity

Rule:
1 HP = 0.8 TR
COP = 3–4

🧠 Meaning:
Helps to convert compressor horsepower to TR and estimate efficiency.

Air Changes per Hour (ACH)

Formula:
ACH = (CFM × 60) ÷ Room Volume

Example:
Room 5×5×3 = 75 m³, Airflow 250 CFM
ACH = (250 × 60) ÷ 75 = 200 ACH

🧠 Meaning:
Indicates how often room air is replaced — higher ACH for cleaner areas.

🔥🔧 Oxygen & Acetylene Use and Safety – Protecting People, Property & ProductivityOxy-acetylene equipment is widely used ...
04/12/2025

🔥🔧 Oxygen & Acetylene Use and Safety – Protecting People, Property & Productivity

Oxy-acetylene equipment is widely used for cutting, welding, brazing, and heating, but it also involves one of the highest risks in industrial operations.
Because oxygen supports rapid combustion and acetylene is highly unstable, even a small mistake can lead to fires, flashbacks, explosions, or severe injuries.

This is why strict safety practices are essential every time these gases are handled.

---

🆘 Why Safety Matters

✔️ Oxygen + fuel gas + ignition = instant fire potential
✔️ Acetylene can decompose explosively under pressure
✔️ Flashbacks can cause regulators, hoses, and cylinders to explode
✔️ Mishandling cylinders can cause projectile hazards

Staying alert and following the rules is not optional — it’s lifesaving.

---

🧯 Common Hazards

🔥 Flashback
🔥 Fire or explosion
🔧 Hose leaks
💨 Oxygen enrichment
💥 Acetylene cylinder instability
⚡ Ignition from sparks/electrical sources
🛠️ Improper regulator or hose connections

Understanding these hazards is the first step to preventing accidents.

---

🛠️ Best Practices for Oxygen & Acetylene Safety

🟦 1. Cylinder Handling

Store oxygen and acetylene cylinders separately (min. 6 m apart or fire wall).

Keep cylinders upright and secured with chain.

Never drop, roll, or drag cylinders.

Keep valves clean and free from grease or oil.

🔥 2. Acetylene Cylinder Safety

Never use acetylene above 15 psi — risk of explosion.

Open the valve only ½ to 1 turn for emergency shutdown.

If a cylinder becomes hot, evacuate and cool with water from a safe distance.

🫁 3. Oxygen Safety Rules

Oxygen does not burn, but it accelerates combustion rapidly.

Keep oxygen away from oil, grease, and flammable materials.

Never use oxygen for cleaning, cooling, or powering tools.

🔧 4. Regulator & Hose Precautions

Use only correct regulators for each gas.

Inspect hoses regularly for cracks, burns, or leaks.

Purge each hose before lighting the torch.

Ensure flashback arrestors/check valves are installed.

🔥 5. Lighting & Shutting Down

Always use an approved striker — no matches, no lighters.

Follow correct sequence:
➤ Open acetylene → ignite → slowly add oxygen

After use: close oxygen first, then acetylene, then bleed lines.

---

🛡️ Critical Do’s & Don’ts

✔️ Do:

🧤 Wear gloves, goggles, flame-resistant clothing
🧯 Keep fire extinguishers nearby
🛠️ Check connections before use
👷 Train all operators on gas handling
🏷️ Label cylinders clearly

❌ Don’t:

🚫 Use damaged hoses or regulators
🚫 Store cylinders in confined or hot spaces
🚫 Mix oxygen with compressed air tools
🚫 Allow smoking near cylinders
🚫 Use acetylene near copper tubing (risk of explosive compounds)

---

🎯 Key Takeaway

Safe oxygen and acetylene use depends on discipline, training, and proper equipment.

Safety is everyone’s responsibility — let’s weld safely, cut safely, and go home safely. 🦺💛

Understanding Motor Nameplate Details – A Must for Electrical & Mechanical Engineers
28/11/2025

Understanding Motor Nameplate Details – A Must for Electrical & Mechanical Engineers

FIRE ALARM SYSTEM AND INTEGRATING TO HVAC EQUIPMENT'S
28/11/2025

FIRE ALARM SYSTEM AND INTEGRATING TO HVAC EQUIPMENT'S

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