1. GASKETED PLATE HEAT EXCHANGER
MME 9516 HVAC 1 PROJECT PRESENTATION
BY
- SALEEM MOHAMMED HAMZA (250873614)

2. OVERVIEW
 INTRODUCTION
 CONSTRUCTION
 FLOW PATTERN IN A PHE
 PLATES
 PLATE MATERIALS
 DESIGN LOGIC FOR HEAT EXCHANGERS
 MEAN FLOW GAP
 CHANNEL HYDRAULIC DIAMETER
 HEAT TRANSFER COEFFICIENT
 CHANNEL MASS VELOCITY
 PRESSURE DROP
 OVERALL HEAT TRANSFER COEFFICIENT
 HEAT TRANSFER SURFACE AREA

3. INTRODUCTION
 Heat exchangers are devices that provide the flow of thermal
energy between two or more fluids at different temperatures
without mixing with each other.
 A Plate Heat Exchanger is a type of heat exchanger that uses
metal plates to transfer heat between two fluids.
 Applications:
 Power Plants
 Process Industries
 Chemical & Food Industries
 Air Conditioning & Refrigeration
 Waste Heat Recovery
 Space Application

4. CONSTRUCTION
 The main elements of plate heat exchanger (PHE) are fixed
frame and compression plate, connecting ports, plates.
 The heat transfer surface is composed of series of plates
with parts for fluid entry and exit in the four corners.
 The plate pack is tightened by means of either a
mechanical or hydraulic tightening device.
 The warmer medium will give some of its heat energy
through the thin plate wall to the colder medium on the
other side.
 Leakage from the plates to the surroundings is prevented
by using gaskets.

5. FLOW PATTERN IN A PHE
 The hot fluid flows through one channel and the cold through
the other channel.
 The fluids flow between alternative passages formed between
two packed plates.
 The flow through the plates is controlled by using gaskets.
 The corrugated pattern on the plate induces turbulence and
thus enhances heat transfer.

6. PLATES
 Most of the commercial plates in PHE are chevron type, which
have a surface corrugation pattern called washboard.
 In chevron type, adjacent plates are assembled such that the flow
channels provides swirling motion to the fluids. This promotes
turbulence by continuously changing flow direction and velocity of
the fluids.
 The corrugated pattern has an angle 𝛽, which is referred to the
chevron angle.
 The chevron angle is reversed on adjacent plates so that when
plates are clamped together, the corrugations provide numerous
contact points.
 The chevron angel varies between the extremes of about 65⁰ and
25⁰ and determines the pressure drop and heat transfer
characteristics of the plate.

7. PLATE MATERIALS
 Plates are made from all malleable materials.
 The most common materials are stainless steel,
titanium, titanium-palladium, aluminum,
aluminum brass, etc.
 Plate material is chosen depending on the type of
heat transfer fluids, type of application and the
environment of use. For example: Titanium plates
are used in sea water and marine applications to
prevent corrosion of plates by the saline water.
 The table shows the different types of plate
material and their thermal conductivity.

8. DESIGN LOGIC FOR HEAT EXCHANGER
 The corrugations increase the surface area of the
plate as compared to the original flat area.
 This is expressed as the surface enlargement
factor, φ which is defined as the ratio of the actual
effective area as specified by the manufacturer, A1,
to the projected plate area A1p
 Where, and ;
 Here DP is the port diameter.
 Φ is between 1.15 and 1.25. In practical application it
is assumed to be 1.17

9. MEAN FLOW GAP
 Flow channel is the conduit formed by two adjacent plates
between the gaskets.
 The mean channel spacing, b, is defined as 𝒃 = 𝒑 − 𝒕
 where p is the plate pitch or the outside depth of the
corrugated plate and t is the plate thickness.
 Channel spacing, b is required for calculating mass velocity
and Reynolds number which is not usually specified for
manufacturer.
 The plate pitch is not to be confused with the corrugation
pitch. Plate pitch is found by:
 Where, Nt is total number of plates and Lc is compressed
plate pact length.

10. CHANNEL HYDRAULIC DIAMETER
 The hydraulic diameter of the channel Dh is defined as,
with approximation b<<Lw
 The heat transfer coefficient will strongly depend on the chevron inclination 𝜷 relative to flow
direction.
 Heat Transfer and friction factor increases with 𝜷.
 Nusselt Number, 𝑁𝑢 =
ℎ𝐷ℎ
𝑘

11. HEAT TRANSFER COEFFICIENT

12. CHANNEL MASS VELOCITY
 The channel mass velocity is given by:
 where, Ncp is the number of channels per pass and is obtained from
 where, Nt is the total number of plates and Np is the number of passes.
 Hence Reynolds number can be found using, 𝑅𝑒 =
𝐺 𝑐 𝐷ℎ
𝜇

13. PRESSURE DROP
 The total pressure drop is composed of the friction channel pressure drop ΔPc and the port pressure drop
ΔPp.
 The friction factor, f is obtained from the above table and Leff is the effective length of the fluid flow path
between inlet and outlet ports.
 The pressure drop in the port ducts Δpp can be roughly estimated as,
 Where,
 Therefore, Total pressure drop, ΔPT = ΔPc + ΔPP

14. OVERALL HEAT TRANSFER COEFFICIENT
 The overall heat transfer coefficient for a clean surface is
 and under fouling conditions (fouled or service overall heat transfer coefficient) is
 Where h and c stand for hot and cold streams respectively.

15. HEAT TRANSFER SURFACE AREA
 The required heat duty, Qr , for cold and hot streams is
 On the other hand, the actually obtained heat duty, Qf , for fouled conditions is defined as
 Where A is total area of effective plates, F is the fouling factor and the true mean temperature difference.
ΔTm, for the counter flow arrangement is given as
 Where ΔT1 and ΔT2 are the terminal temperature differences at the inlet and outlet.

16. ADVANTAGES
 The gasket design minimizes the risk of internal leakage. Any failure in the gasket results in leakage to
the atmosphere which is easily detectable on the exterior of the unit.
 Flexibility of design through a variety of plate sizes and pass arrangements.
 Efficient heat transfer, high heat transfer coefficient for both fluids because of turbulence and a small
hydraulic diameter.
 Very compact (large heat transfer area to volume ratio) and low in weight in spite of their compactness.
 The heat losses are negligible and no insulation is required as only the plate edges are exposed to the
atmosphere.
 Plate units exhibits low fouling characteristics due to high turbulence.