Industrial Engineering, 3D CAD & Supplier Sizing Platform
Size thermal, fluid & mechanical systems with verified manufacturer catalogs & 3D CAD tools.
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01
3D CAD · STEP · DXF
ALVC Design Studio
3D CAD (.STEP/.IGES/.DXF), 2D Sketcher, Extrude/Revolve & Assembly BOM.
STEP · STL · DXF · BOM
Open →
02
Song–Lee–Moran
Heatsink & Vapor Chamber Sizer
Thermal resistance, spreading performance & source temperature for extruded and ALVC heatsinks.
ALVC × KERAFOL®
Open →
03
Gnielinski
Liquid Cold Plate Sizer
Pressure drop Δp, Gnielinski convection & surface ΔT for liquid cold plates.
R_th · Δp · T_j
Open →
04
Louvered Fin
Brazed Radiator & Evaporator Core
Flat-tube louvered-fin core sizing for Q_WT, evaporator Q_VD & airside Δp.
H_core · Q_WT · Δp
Open →
05
ε–NTU / VDI G6
Heat Exchanger Sizer (LMTD / NTU)
Counterflow, parallel & crossflow plate HX sizing with LMTD, ε-NTU & chevron β.
LMTD · ε-NTU · A_req
Open →
06
ISO 9906
Pump & Cooling Loop Sizer
Pump H(V̇) and system curve intersection with hydraulic power, BEP & NPSH margin.
V̇_op · Δp · NPSH
Open →
07
SiC / R290
EV Inverter & Chiller Loop
Coupled glycol & R290 chiller loop for SiC/IGBT T_j, evaporator & compressor.
T_j · Q_evap · COP
Open →
08
ASHRAE W1–W4
Data Center Free-Cooling & PUE
Direct-to-chip DLC split, ASHRAE W1–W4 free-cooling hours, annual PUE & OPEX.
PUE · DLC % · OPEX
Open →
09
IEC 60890
Cabinet Cooling Sizer (IEC 60890)
IEC 60890 enclosure heat balance for area A_e, filter fan airflow & air-water HX.
A_e · V̇_fan · Q_HX
Open →
10
ASTM D5470
Thermal Interface (TIM) Selector
Bondline impedance Z_th, contact R_th & ΔT across gap pads, films, pastes & PCM.
ALVC × KERAFOL®
Open →
Boiling & Critical Heat Flux (CHF)
Rohsenow nucleate boiling and Kutateladze–Zuber CHF limit for Water, Methanol, R134a, and R1233zd(E).
Two-Phase & Boiling
Open Tool →
Finned-Tube Coil Simulator
Moving-boundary finned-tube condenser, wet-coil evaporator, and R744 gas-cooler sizing with CoolProp properties.
HVAC & Refrigeration Coils
Open Tool →
Component or Material Manufacturer?
Integrate verified thermal, fluid, and mechanical component data directly into live system sizing.
Heatsink & Vapor Chamber Sizer
ALVC × 
KERAFOL — Thermal PartnerR_th,total = 0.175 K/W · Max Source Temperature = 78.6 °C · Mean Air Rise ΔT_air = 9.4 K
Thermal Resistance
0.175 K/W
Spreading Resistance
0.013 K/W
Source Temperature
78.6 °C
Fin Efficiency
89.3 %
3D Cooler Assembly
ALVC Vapor Chamber
TIM Interface
Heat Source(s)
Al 6063 Base & Fins
Thermal Resistance
Fin Gap: 3.3 mm
| Resistance Breakdown (ALVC Pocket-Inlay · Config F) | K/W | ΔT at 250 W [K] | Share |
|---|
ALVC-T4.0W46 × 2 (4.0×46 mm) • Cap: 250 / 300 W • Web s_rest = 6.0 mm • Bare Interface (R_TIM = 0.0000 K/W)
ΔT vs. Solid Al 6063: −18.4 K (Al 6063 R_th = 0.248 K/W)
Application Note: Sizes heatsinks across Solid Al 6063, ALVC Inlay, and Direct ALVC + Fins with ALVC × KERAFOL® TIM & 3D Thermal & Airflow Analysis.
▸ Governing Equations, Assumptions & Standards
1. Convective Heat Transfer & Fin Efficiency (Forced & Natural Convection)
η_f = tanh(m · H_f) / (m · H_f) where m = √[2 · h / (k_f · t_f)], A_eff = A_base,exposed + η_f · A_fins
Nu_L = max[0.664 · Re_L^(1/2), 0.037 · Re_L^(0.8) − 871] · Pr^(1/3) | R_air = 1 / (2 · ṁ · c_p), ṁ = ρ · v · (N − 1) · s · H_f
2. Two-Stage Compound Base Spreading (Muzychka, Yovanovich & Culham 2004 / Lee et al. 1995)
k_xy = √(k_x · k_y), k_eff = √(k_xy · k_z), t_eff = t_p · √(k_xy / k_z)
Arch 2 (ALVC Inlay): R_base = R_1D + R_sp(A_src → A_cooler) | Arch 3 (Direct Fins on ALVC): R_base = R_1D,vc + R_sp,vc(A_src → A_cooler)
3. ALVC × KERAFOL® TIM Coupling & Mechanical Envelope
R_th,TIM = Z_TIM(P, R_a) / A_src | R_th,sys = R_th,TIM + R_conv + R_air + R_1D + R_sp
4. 3D Conjugate Heat Conduction & Developing-Channel Airflow
3D conjugate solid conduction & streamwise ε-NTU air energy balance • Teertstra (1999) / Gnielinski developing h(z) • Elenbaas buoyancy + view-factor radiation F = s/(s+H) • Shah & London Δp_air + Lee (1995) unducted bypass.
ISO 10303-21 (STEP CAD Space-Claim) • DIN EN ISO 10211 • VDI Heat Atlas Chapter C & M1 • KERAFOL® KERATHERM® Catalogue 06/2026.
- Steady-state analytical and 3D conjugate thermal-airflow models evaluate source hotspot temperature, fin efficiency, air warm-up, and channel pressure drop under the selected boundary conditions.
- Extruded ALVC two-phase profiles are rated for horizontal (0°) or vertical bottom-heated (90°) mounting orientations.
Assistant
Step 1 of 8 · Heat Power
How much heat power must be dissipated?
Enter the total thermal power generated by your heat source.
W
Thermal load: 250 W · Heat flux: 15.6 W/cm² (on 40 × 40 mm)
Step 2 of 8 · Heat Source
What are your heat source dimensions?
Enter contact width and length of the heat source in millimeters.
×
Contact area: 16.0 cm² · Heat flux: 15.6 W/cm²
Step 3 of 8 · Available Cooler Footprint
What is your available cooler footprint?
Enter maximum allowable heatsink width, length, and fin height.
×
×
Footprint: 196.0 cm² · Total height incl. baseplate: 55 mm
Step 4 of 8 · Air Flow
What airflow is available across the fins?
Enter air velocity or volumetric flow (0 = silent natural convection).
Forced convection · Equivalent flow: 45.4 m³/h (26.7 CFM)
Step 5 of 8 · Ambient Temperature
What is the ambient air temperature?
Enter the maximum inlet air temperature reaching the heatsink.
°C
Inlet air: 35.0 °C · Target ΔT budget: 50.0 K (max 85.0 °C)
Step 6 of 8 · Thermal Resistance
What is your target thermal resistance?
Enter maximum allowable system thermal resistance (including TIM).
K/W
Implied max source temperature: 85.0 °C (ΔT = 50.0 K at 250 W)
Step 7 of 8 · Thermal Interface (KERAFOL®)
What interface condition applies?
Select isolation or gap requirement to pair the right KERAFOL® TIM.
KERATHERM® KP 12 (10.0 W/m·K, 25 μm) · R_tim = 0.002 K/W
Step 8 of 8 · Result
Recommended System
✓ Within target
Cooler
0.175 K/W
Heatsink with ALVC Inlay (2× ALVC-T4.0W45.8)
140 × 140 × 45 mm · 250 W · 2.5 m/s
Thermal Interface · KERAFOL®
+ 0.002 K/W
KERATHERM® KP 12
10.0 W/m·K · 25 μm BLT · 40 × 40 mm
System R_th (≤ 0.200)
0.176 K/W
Source Temp.
79.0 °C
vs. Solid Al 6063
−18.3 °C
Liquid Cold Plate Sizer
Δp = 1.9 kPa · R_th = 0.0092 K/W · Surface T_max = 40.4 °C
Pressure Drop
1.9 kPa
Thermal Resistance
0.0092 K/W
Reynolds Number
4,153
Max Surface Temp
40.4 °C
| Cold Plate Resistance & Hydraulic Breakdown | R_th [K/W] | ΔT [K] | Share / Telemetry |
|---|
Pressure Drop & Thermal Resistance vs. Flow Rate
Flow Speed: 0.59 m/s
Application Note: Solves Darcy–Weisbach pressure drop (with port/bend losses), laminar/Gnielinski Nusselt heat transfer, and wall conduction across Al 6063, Al 6061, and Cu C11000 cold plates.
▸ Governing Equations, Assumptions & Standards
1. Darcy-Weisbach Pressure Drop & Friction Factor
Δp = [f · (L / D_h) + K_port + (N_pass - 1) · K_bend] · (ρ · v² / 2) | Churchill (1977), all regimes, continuous: f = 8 · [(8/Re)^12 + (A + B)^-1.5]^(1/12), A = [-2.457 · ln((7/Re)^0.9 + 0.27 · ε/D)]^16, B = (37530/Re)^16 (smooth channel ε/D = 0; → 64/Re laminar, ≈ Colebrook turbulent). Rectangular channels: laminar f·Re = 96·(1 - 1.3553α + 1.9467α² - 1.7012α³ + 0.9564α⁴ - 0.2537α⁵) (Shah & London 1978), blended to Churchill between Re 2300 and 4000.
2. Convective Heat Transfer
Re < 2300: Nu = Nu_fd (4.364 round; 8.235·(1 - 2.0421α + 3.0853α² - 2.4765α³ + 1.0578α⁴ - 0.1861α⁵) rectangular, uniform heat flux; fully developed, no entrance enhancement - conservative, no wall-viscosity correction) | 2300 ≤ Re < 10⁴: Nu = (1 - γ) · Nu_fd + γ · Nu_G(10⁴), γ = (Re - 2300) / (10⁴ - 2300) (Gnielinski, VDI Heat Atlas G1) | Re ≥ 10⁴: Nu = [(f/8) · (Re - 1000) · Pr] / [1 + 12.7 · √(f/8) · (Pr^(2/3) - 1)], f = (0.79 · ln Re - 1.64)^-2
R_conv = 1 / (h · A_wet), A_wet = n · P · L | R_cond = t_w / (k_w · A_src) | R_th = R_conv + R_cond | T_max = T_in + ΔT_fluid + Q · R_th [outlet-side worst case]
Fluid properties at the mean fluid temperature T_in + ΔT_fluid / 2 (3 fixed-point iterations); ΔT_fluid = Q / (ρ · V̇ · c_p).
3. Context & Fluid References
Methods: Churchill 1977 • Gnielinski 1976/VDI Heat Atlas • Shah & London 1978 • fluid data CoolProp 8.0 (incompressible mixtures by mass fraction). No standard is certified or applied by this calculation.
- Uniform heat flux over the wetted channel area; the plate material, wall thickness and source footprint define the 1-D wall resistance (constriction/spreading between the channels and contact/TIM resistance are not included).
- Minor losses are modelled with loss coefficients on the channel dynamic pressure: K_port (inlet + outlet, default 1.5) and K_bend per 180° bend (default 1.0) — both editable assumptions. The number of bends is passes − 1.
- The STEP export is an outer envelope without channels; its size is not coupled to the calculation.
Thermal Interface (TIM) Selector
ALVC × KERAFOL — Thermal PartnerInterface Temperature Drop ΔT = 2.4 °C at 11.2 W/cm²
Interface ΔT
2.4 °C
Interface R_th
0.013 K/W
Thermal Impedance
0.21 K·cm²/W
Heat Flux
11.2 W/cm²
Interface Temperature Drop ΔT & Thermal Resistance Comparison
P = 45 psi · A = 16 cm²
KERATHERM® catalogue materials at your conditions
Nominal datasheet values per KERAFOL® technical documentation (06/2026, ASTM D5470) · click a row to select the material
| Material | Type | λ [W/m·K] | d used [mm] | Z [K·cm²/W] | ΔT [°C] | Ud [kV AC] | Hardness | T range [°C] |
|---|
Catalogue values (λ, thickness, Ud, hardness, T range, Rth) per KERAFOL® datasheet (engineer guidance only). Z adds contact resistance from your surface roughness and pressure; Ud applies at catalogue test thickness (* = clamped to catalogue range; >30 % pad compression flagged).
Application Note: Models 1D bulk conduction and pressure-dependent contact resistance across 5 generic TIMs and 15 KERAFOL® KERATHERM® series (ASTM D5470).
▸ Governing Equations, Assumptions & Standards
1. Total Thermal Impedance Chain
Z_TIM = R_c1 + BLT / k_TIM + R_c2 [m²K/W; shown in K·cm²/W] | R_th = Z_TIM / A_contact (Prasher 2006, Proc. IEEE 94:1571)
2. Bond-Line Thickness vs. Pressure
Paste / molten PCM (squeeze flow of a particle-laden yield-stress fluid, form after Prasher et al. 2003): BLT = max(BLT_min, C · (τ_y / P)^0.166), C = 31 μm, BLT_min = 10 μm (filler limit); PCM: BLT = min(t_0, …) [C, τ_y and BLT_min are editable ALVC assumptions; the exponent and constant have not been verified against the original paper] | Gap pad: BLT = t_0 · (1 - ε(P)), ε(P) from a typical compression curve of a 3 W/mK Shore 00 45 elastomer pad (7 / 10 / 20 / 30 % deflection at 5 / 10 / 25 / 50 psi, log-linear beyond, ≤ 60 %; not a datasheet of a specific product) | Indium foil, graphite sheet: BLT = t_0
3. Contact Resistance at Each Interface (i = 1 die/lid, 2 heatsink; substrates selectable)
σ_i = 1.25 · Ra_i (Gaussian surface), asperity slope m_i = 0.125 · (σ_i/μm)^0.402 (Antonetti; 0.216–9.6 μm), k_s = 2 k_TIM k_sub / (k_TIM + k_sub); the TIM face is taken as smooth / conforming
Solid foils / sheets (indium, graphite): joint conductance h_j = h_c + h_g, h_c = 1.25 k_s (m/σ) (P/H_c)^0.95 (Cooper–Mikic–Yovanovich plastic, 10^-6 ≤ P/H_c ≤ 0.23), h_g = k_air / (Y + M), Y = 1.53 σ (P/H_c)^-0.097, M_air = 0.373 μm (Yovanovich et al. 1997); R_c = 1/h_j
Elastomer gap pad: Mikic elastic contact h_c = 1.54 k_s (m/σ) (P/H_e)^0.94, H_e = E' m / √2, E' = E_sec(P)/(1 - ν²), ν = 0.49; P/H_e ≥ 1 → fully conformed (capped at 1) | Paste / molten PCM: R_c1 + R_c2 = (σ_1 + σ_2)/(2 k_TIM) · (A_nominal/A_real) with A_real = A_nominal (fully wetted, P >> τ_y; lower bound) (Prasher 2001)
4. Context & Practical Limits
Test-method context (no test is performed by this tool): ASTM D5470 (guarded heat flow meter) for thermal impedance. Literature (methods, not certifications): Prasher 2001/2003/2006, Mikic 1974, Yovanovich et al. 1997, Gent 1958, Antonetti.
- Assumed material parameters (typical, replace with the product datasheet): paste τ_y = 1 kPa; PCM (molten) τ_y = 10 kPa; indium H_c = 8.8 MPa (Brinell 0.9); graphite sheet H_c = 50 MPa; k_TIM = nominal datasheet values.
- Flat, clean mating surfaces (flatness / warpage not modelled); substrates selectable (default: die lid copper k = 390 W/mK, heatsink aluminium k = 200 W/mK).
- Phase change materials (PCM) are evaluated in the molten state; a warning appears if the operating temperature is below the phase-change temperature (generic PCM about 45 °C, KERAFOL® PCM 16125C softening interval 52–54 °C).
- KERAFOL® KERATHERM® library: λ, thickness range, breakdown voltage, hardness, temperature range and Rth are the values published in the KERAFOL KERATHERM® catalogue 06/2026 (Rth measured on a 4 cm² sample, catalogue test methods). Model assumptions on top: tapes are thin films at the catalogue thickness with elastic contact (E from Shore A, Gent 1958); gap pads are evaluated at the installed thickness you set, exactly like the catalogue Rth (no compression credit; the generic compression curve above only drives the 30 % flag and the contact modulus); 2K gap fillers fill the gap you set (wetting contact); KP greases use the catalogue measuring thickness of 25 μm; PCM uses the generic PCM rheology. For gap-driven products the catalogue Rth is scaled linearly from its reference thickness to your thickness before the comparison. The breakdown voltage Ud is taken as published at the catalogue reference thickness (GFL 3030: 0.5 mm); thinner layers are shown with “?” (not guaranteed). Z of the table = bulk + contacts of your surfaces, so it can exceed the catalogue basis d/λ.
Heat Exchanger Sizer (LMTD / NTU)
Counterflow · Q = 45.0 kW · LMTD = 29.8 K · Area A = 0.54 m²
Heat Duty
45.0 kW
Mean Temp Difference
29.8 K
Required Surface Area
0.54 m²
Thermal Effectiveness
37.3 % (0.54)
| Stream | Fluid | T_in [°C] | T_out [°C] | Mass Flow [kg/s] | Capacity C [kW/K] | ρ · c_p |
|---|
Temperature Profile & Minimum Pinch
Pinch ΔT_min = 31.2 K
Overall Heat Transfer
Film Heat Transfer
Reynolds Numbers
Pressure Drops
Installed vs. Req. Area
Installed vs. Req. Plates
Surface Enlargement
Active Flow Channels
| Side | w [m/s] | Re [–] | Pr [–] | ξ [–] | Nu [–] | h [W/m²K] | Δp ch [kPa] | Δp port [kPa] | Δp tot [kPa] |
|---|
Which HX Model do I need?
Application Note: Solves LMTD and ε-NTU heat exchanger duty across counterflow, parallel, and crossflow, plus Martin (1996) / VDI M6 chevron plate sizing (Cu/Ni/Al BPHE & bolted GPHE).
▸ Governing Equations, Assumptions & Standards
1. Log-Mean Temperature Difference & Sizing Area
LMTD = (ΔT_1 - ΔT_2) / ln(ΔT_1 / ΔT_2) | A_req = Q_dot / (U · F_corr · LMTD)
2. Effectiveness-NTU Formulation (ε-NTU)
NTU = (U · A) / C_min | ε_counter = [1 - exp(-NTU(1 - C_r))] / [1 - C_r · exp(-NTU(1 - C_r))] | ε_parallel = [1 - exp(-NTU(1 + C_r))] / (1 + C_r)
Crossflow, both unmixed: ε = 1 - exp[(NTU^0.22 / C_r) · (exp(-C_r · NTU^0.78) - 1)] (solved for NTU by bisection; F · LMTD = Q / UA)
3. Plate Heat Exchanger Mode — Martin (1996) / VDI Heat Atlas M6
Area factor: X = πb/Λ = π/4 (Λ = 4b) | Φ = (1/6)·[1 + √(1+X²) + 4·√(1+X²/2)] = 1.1412 | d_h = 2b / Φ
Plates & channels (1/1 pass): N_eff = N_p − 2 | A_avail = N_eff · Φ · L_p · W_p | N_ch,hot = floor((N_p−1)/2), N_ch,cold = ceil((N_p−1)/2)
Channel flow: w_i = V̇_i / (N_ch,i · b · W_p) | Re_i = ρ_i · w_i · d_h / μ_i | Pr_i = c_p,i · μ_i / k_i (properties at the mean temperature of each stream, iterated)
Friction: ξ_0 = 64/Re (Re < 2000), (1.8·lg Re − 1.5)−2 (Re ≥ 2000) | ξ_1 = 3.8·(597/Re + 3.85) (Re < 2000), 3.8·39/Re0.289 (Re ≥ 2000)
1/√ξ = cosφ / √(0.18·tanφ + 0.36·sinφ + ξ_0/cosφ) + (1 − cosφ) / √ξ_1
Heat transfer (generalised Levêque): Nu_i = 0.122 · Pr_i1/3 · [ξ_i · Re_i² · sin 2φ]0.374 | h_i = Nu_i · k_i / d_h
1/U_calc = 1/h_hot + δ_w/k_w + 1/h_cold + R_f | A_req = UA / U_calc | N_p,req = 2 + ceil(A_req / (Φ · L_p · W_p))
Pressure drop per side: Δp_i = ξ_i · (L_p/d_h) · ρ_i·w_i²/2 + 1.5 · ρ_i·w_port,i²/2 with w_port,i = V̇_i / (π/4 · D_port²)
4. Literature Sources (methods, chapter numbers not individually verified)
H. Martin, "A theoretical approach to predict the performance of chevron-type plate heat exchangers", Chem. Eng. Process. 35 (1996) • VDI Heat Atlas (plate heat exchanger section) • Kays & London "Compact Heat Exchangers" • Incropera ε-NTU relations.
- Zero external shell heat loss to ambient. Fluid properties are taken at the mean stream temperatures T_in −/+ Q/(2·C) (3 fixed-point passes) in both modes; tables end at 120 °C (water, oil, air) / 100 °C (glycols) and a note appears if the mean temperature lies outside.
- Second-law limit: Q ≤ C_min · (T_h,in - T_c,in); the requested duty is capped at 97 % of the arrangement’s asymptotic effectiveness (finite area).
- Plate mode: wall resistance δ_w/k_w per construction (Cu-BPHE 0.40 mm, Ni-BPHE 0.45 mm, GPHE 0.55 mm stainless steel k_w = 16.2 W/m·K; Al-BPHE 0.80 mm k_w = 190 W/m·K); plate sizes S1…XL1 are nominal ALVC presets, not a manufacturer catalogue.
- Plate mode: the viscosity ratio (η/η_wall)1/6 of the Martin correlation and a temperature-dependent port distribution are neglected; the hot stream has floor((N_p−1)/2) and the cold stream ceil((N_p−1)/2) channels (1/1 pass); the selected flow arrangement sets the NTU relation, a real chevron plate pack is close to counterflow.
- Plate mode: ξ is blended smoothly between laminar and turbulent branch over Re = 1500…2500 (smoothstep, cubic) so that U and Δp have no jump at Re ≈ 2000; outside that window the Martin (1996) expressions are used unchanged. N_p,req is evaluated at the installed plate count (velocity, and thus U, depend on N_p).
- Crossflow uses the approximation above (about −5 … +5 % in area against the exact solution). Plate mode: the corrugation wavelength Λ = 4b is fixed, Φ = 1.1412 is the exact value of the formula (an earlier specification rounded it to 1.1407), the channel length for Δp is the nominal plate length L_p of the preset, the port loss term 1.5 · ρ · w_port²/2 is an ALVC assumption, and the sizing mode does not recompute Q from the installed plates. Operating pressure is only compared with p_max of the construction; hydraulic power is Δp·V̇ (no pump efficiency).
- Plate mode: Martin’s correlation is a liquid-side correlation — the dry-air option is flagged; Re outside 10…20 000 is flagged as extrapolation.
Pump & Cooling Loop Sizer
Operating Point: 23.45 L/min @ 9.25 m (90.7 kPa) · P_elec = 57.2 W
Operating Flow Rate
23.45 L/min
Operating Pressure Head
9.25 m (90.7 kPa)
Electrical Pump Power
57.2 W (35.5 W hyd)
Cavitation Margin
+2.4 m (SAFE)
Pump Curve vs. System Resistance & Efficiency
ISO 9906 • Cavitation NPSH Check
Application Note: Solves the pump/loop intersection H_pump(V̇) = H_sys(V̇), hydraulic and electrical power, and cavitation NPSH margin from inlet suction pressure and fluid temperature.
▸ Governing Equations, Assumptions & Standards
1. Operating Point Intersection Equation
H_pump(V) = H_0 - a · V² | H_sys(V) = H_stat + k_sys · V² | V_op = √[(H_0 - H_stat) / (a + k_sys)]
2. Hydraulic & Electrical Power Formulation
P_hyd = ρ · g · (V_op / 60000) · H_op [W] | P_elec = P_hyd / η [constant η at the operating point; away from the best-efficiency point the real efficiency is lower and P_elec higher]
3. Cavitation Check (NPSH Margin)
NPSH_A = (p_suct,gauge + p_atm - p_vap(T)) / (ρ(T) · g) [p_atm = 101.325 kPa; p_suct = gauge pressure at the pump inlet, so static head and suction-line losses are already contained in it; velocity head neglected (conservative)] | ΔNPSH = NPSH_A - NPSH_R ≥ 1.0 m (Safe Margin)
p_vap(T), ρ(T) of water from the CoolProp saturation / fluid tables; water-glycol: ρ from CoolProp, p_vap by Raoult’s law p_vap ≈ x_water · p_sat,water(T) (approximation). Negative suction gauge pressure (vacuum, suction lift) is allowed down to −0.9 bar(g).
Terminology context only (no test grade or tolerance of these documents is applied): ISO 9906 (rotodynamic pump tests), Hydraulic Institute HI 1.3 / 9.6, DIN EN ISO 5199.
- Incompressible fluid; ρ and p_vap are evaluated at the entered fluid temperature at the pump inlet.
- The pump curve is a parabola H_0 − a·V² with constant efficiency; the efficiency line in the chart is an assumption, not a pump curve. With a BEP flow entered, the preferred operating region 70…120 % of BEP is shown and checked.
- The NPSH check is meaningful for closed, pressurised loops and for open systems with suction lift (enter the resulting gauge pressure at the pump inlet, including losses).
Boiling & Critical Heat Flux (CHF)
Operating Heat Flux: 56.0 W/cm² · Zuber CHF = 126.0 W/cm² · Safety Factor = 2.25
Operating Heat Flux
56.0 W/cm²
Critical Heat Flux
126.0 W/cm²
Burnout Safety Factor
2.25 (SAFE)
Wall Temperature Rise
4.8 K (Tw = 104.8 °C)
Boiling Heat Flux vs. Wall Temperature Rise
Rohsenow / Cooper • Ivey–Morris Subcooling
Application Note: Calculates nucleate pool-boiling wall superheat (Rohsenow / Cooper) and Zuber–Lienhard CHF across smooth, sintered-wick, and micro-grooved surfaces.
▸ Governing Equations, Assumptions & Standards
1. Zuber-Kutateladze Critical Heat Flux Limit
q''_CHF = C_chf · h_lv · √(ρ_v) · [σ · g · (ρ_l - ρ_v)]^(0.25) · f_surface [W/m²] | C_chf = 0.149 (Lienhard–Dhir, large flat plate; Zuber’s original value π/24 = 0.131), same for all fluids, editable | all properties evaluated at T_sat (CoolProp 8.0 saturation tables) | water at 1 atm: 126.1 W/cm²
Ivey-Morris subcooling: q''_CHF,sub = q''_CHF · min[ 1 + 0.1 · (ρ_l / ρ_v)^0.75 · c_p,l · ΔT_sub / h_lv ; f_cap ] | f_cap = 3.0 (engineering limit, editable; the validity range of the correlation is not checked) | T_sat ≥ T_c: supercritical, no boiling
2. Nucleate Boiling Superheat (two correlations)
Rohsenow (1952): q''_nucleate = μ_l · h_lv · [√(g(ρ_l - ρ_v)/σ)] · [c_p,l · ΔT_e / (C_s,f · h_lv · Pr_l^n)]³ | n = 1.0 (water), 1.7 (other fluids) | C_s,f is a constant of the fluid–surface pair (water on polished copper: 0.013)
Cooper (1984): h = 55 · p_r^(0.12 − 0.2·log10 R_p) · (−log10 p_r)^(−0.55) · M^(−0.5) · q''^0.67 [W/m²K, q'' in W/m², R_p in µm, M in kg/kmol] | ΔT_e = q'' / h | p_r = p_sat / p_crit, valid for p_r = 0.001 … 0.9, M = 2 … 200; needs no surface-pair constant
Auto: Rohsenow for water, Cooper for methanol and the refrigerants (their C_s,f is not available). For q'' > q''_CHF the wall superheat is not defined (film boiling) and is not displayed.
3. Margins, Surfaces & Limits
Rohsenow (1952), Zuber (1959), Lienhard & Dhir (1973), Ivey & Morris (1962), Cooper (1984): literature correlations; no standard or pressure-vessel code is applied.
- Safety factor SF = q''_CHF / q'': SAFE ≥ 1.5, CAUTION 1.2 … 1.5, BURNOUT RISK < 1.2 (ALVC design margins by convention, not from a standard).
- The values for the wick and micro-grooved surfaces (C_s,f, CHF factor) are assumptions without measurement data; replace them with measured values.
- The boiling curve is calculated up to CHF. Natural convection and the onset of nucleate boiling are not modelled; the branch beyond CHF (transition, film boiling) is schematic. The minimum heat flux shown follows Zuber/Berenson, q''_min = 0.09 · ρ_v · h_lv · [σ g (ρ_l − ρ_v) / (ρ_l + ρ_v)²]^0.25.
- Pool boiling on a horizontal flat surface facing upward; no flow boiling, no confinement, saturated bulk apart from the subcooling input.
Cabinet Cooling Sizer (IEC 60890)
Uncooled Internal Air: 87.4 °C · Fan Airflow: 368.5 m³/h (216.9 CFM)
Passive Wall Cooling
286.0 W (19.1 %)
Required Airflow (m³/h)
368.5 m³/h
Required Airflow (CFM)
216.9 CFM
Water Cooler Duty
1.21 kW (3.5 L/min)
Required Fan Airflow vs. Allowed Temperature Rise
DIN EN 60890 Table 3 • ISA Altitude Derating
Application Note: Solves steady-state enclosure heat balance using IEC/TR 60890 Table 3 effective area A_e, comparing passive wall dissipation, altitude-corrected filter-fan airflow, and air-to-water HX cooling.
▸ Governing Equations, Assumptions & Standards
1. Enclosure Heat Balance (linear approximation)
T_int,uncooled = T_amb + Q_v / (k · A_eff) | Q_s = k · A_eff · (T_int,target - T_amb) [k = 5.5 W/m²K default, editable; constant, independent of ΔT, height and paint]
A_eff = Σ A_0 · b (IEC/TR 60890 Table 3; b = 1.4 exposed roof, 0.7 covered roof, 0.9 exposed side face, 0.5 covered side face / side face of a central enclosure, floor not counted). Installation types: (1) single, detached A = 1.8·H·(W+D) + 1.4·W·D | (2) single, wall-mounted A = 1.4·W·(H+D) + 1.8·D·H | (3) first/last in a row, detached A = 1.4·D·(H+W) + 1.8·W·H | (4) first/last, wall-mounted A = 1.4·H·(W+D) + 1.4·W·D | (5) central, detached A = 1.8·W·H + 1.4·W·D + D·H | (6) central, wall-mounted A = 1.4·W·(H+D) + D·H | (7) central, wall-mounted, covered roof A = 1.4·W·H + 0.7·W·D + D·H | Benchmark: A_eff = 5.2 m² fixed
T_int ≤ T_amb: filter-fan cooling impossible → active cooling duty Q_cool = Q_v + k · A_eff · (T_amb - T_int) | Q_s is the wall capacity at T_int (if Q_s ≥ Q_v the wall alone is sufficient)
2. Forced-Air Filter Fan Flow Rate
V_dot = (Q_v - Q_s) / [ρ_air · c_p,air · ΔT_target] | ρ_air = p(z) / (R · T_amb) at the fan inlet (ambient) | p(z) = 101325 · (1 - 2.25577·10⁻⁵ · z)^5.25588 (ISA, DIN ISO 2533) | c_p,air = 1005 J/kgK | CFM = m³/h · 0.588578
Air-water heat exchanger: Q_hx = max(0, Q_v - Q_s) | water flow = Q_hx / (c_p,w · ΔT_w), c_p,w = 4.184 kJ/kgK, ρ_w ≈ 1 kg/L, ΔT_w editable (default 5 K); no safety margin
3. Standards & Limits
IEC/TR 60890 (DIN VDE 0660-507): only the effective cooling surface A_e and the seven installation types of Table 3 are used. The temperature-rise verification of IEC/TR 60890 and IEC 61439-1 (heat-dissipation constants, height distribution of the air temperature) is not implemented. DIN ISO 2533: ISA pressure formula.
- The reference case (A_eff = 5.2 m², Q_v = 1500 W, 35 / 45 °C, z = 0 m) is an ALVC regression case, not a test case of the standard.
- k is a typical value for painted sheet steel; real overall coefficients are about 3.5…5.5 W/m²K and fall with smaller ΔT, so the wall capacity may be overestimated at small ΔT (airflow slightly too small).
- Notes are issued above T_int,uncooled = 120 °C (linear estimate no longer meaningful), above 1000 m³/h (beyond usual filter fans) and below ΔT_target = 3 K (ALVC guide values).
- Sealed IP54/IP65 installations require air-to-water heat exchangers if the internal heat load exceeds the passive wall capacity.
Data Center Free-Cooling & PUE
Coolant Flow: 574.2 L/min · Design PUE = 1.100 · Annual Savings: 275,940 € (1,533 MWh)
Coolant Flow Rate
574.2 L/min
Instantaneous PUE
1.082 (Free Cooling)
Cooling Overhead Power
41.2 kW (8.2 % IT)
Annual Cost Savings
275,940 € (1,533 MWh)
Free-Cooling Hours
—
Facility Efficiency vs. Outdoor Temperature
ASHRAE TC 9.9 • PVGIS ERA5 TMY
Application Note: Models warm-water data-center DLC + air-side cooling with dry cooler and series trim chiller across 8,760 h European climate bins to compute facility PUE, free-cooling hours, and annual OPEX savings.
▸ Governing Equations, Assumptions & Standards
1. Heat Split & Coolant Flow
Q_liq = P_IT · f_DLC | Q_air = P_IT · (1 - f_DLC) | V_dot = Q_liq / (ρ · c_p · ΔT_loop) [ρ, c_p of the selected coolant at the mean loop temperature T_sup + ΔT/2, CoolProp 8]
2. Dry Cooler with Series Trim Chiller
T_free = T_sup - ΔT_appr | chiller share of the load x = clamp[ (T_amb + ΔT_appr - T_sup) / ΔT_loop ; 0 ; 1 ] (liquid loop: ΔT_loop as entered; air side: T_sup,air and 6 K water spread)
P_chiller = x · Q / COP | COP = clamp[ η_C · T_ev / (T_cd - T_ev) ; 1.5 ; 10 ] | T_ev = T_sup - 3 K, T_cd = T_amb + 10 K (absolute temperatures) | free-cooling COP = Q_liq / (P_pump + P_fan,liq)
3. Facility PUE (component model)
PUE = 1 + [ f_loss · P_IT + P_pump + P_fan + P_air,aux + P_chiller,liq + P_chiller,air ] / P_IT
P_pump = V_dot · Δp / η_p | P_fan = w_fan · (P_IT + P_chiller) | P_air,aux = w_air · Q_air (the PUE therefore depends on the DLC split, ΔT_loop, the coolant and T_amb)
4. Annual Energy & Financial Savings
Temperature-bin method (climate site): ΔE_annual = Σ_bins h_i · (PUE_baseline - PUE(T_i)) · P_IT / 1000 [MWh/yr; T_i = bin centre, 1 K bins of dry-bulb hours, Σ h_i ≈ 8760] | free-cooling hours = Σ h_i · (share of the bin at or below T_free) | Savings = ΔE_annual · 1000 · Cost_elec [€/yr]
Single-temperature option (legacy basis): ΔE_annual = (PUE_baseline - PUE(T_amb)) · P_IT · 8760 / 1000
Classification context only, no compliance check is made: ASHRAE TC 9.9 liquid-cooling classes, The Green Grid PUE definition, temperature-bin method. Climate data: 24 European stations, 8,760 h/yr typical year (EU JRC PVGIS v5.2 TMY from ECMWF ERA5 reanalysis, ISO 15927-4; DWD/BBSR test reference years) — not a measured year.
- All electrical coefficients (losses, pressure drop, pump efficiency, fan and air-side power, Carnot efficiency, air-side supply temperature) and the baseline PUE are assumptions with the defaults shown in the sidebar; the annual saving is dominated by them and by the baseline PUE.
- A typical year does not contain extreme years or peaks; free-cooling hours react strongly to a 1 K shift (the range for ±1 K is shown with the site note). Hours are rounded to 10 h.
- Dry-bulb bins are used (dry cooler, no adiabatic pre-cooling); the baseline PUE is taken as constant over the year; the IT load is constant.
- Free-cooling hours refer to the liquid loop (100 % of the DLC load without chiller); the air side has its own, lower limit temperature.
EV Inverter & Chiller Loop
Coolant T_in = 24.92 °C (ΔT = 3.08 K) · SiC T_j = 32.1 °C · Chiller Duty = 10.27 kW
Coolant Inlet Temp
24.9 °C (ΔT = 3.08 K)
Semiconductor Temp
32.1 °C (Safe < 150 °C)
Refrigerant Mass Flow
317.8 kg/h (17.3 m³/h)
Chiller Cooling Power
10.27 kW (+101 %)
Chiller Cooling Capacity vs. Compressor Speed
CoolProp 8 Saturation Tables • ISO 21498
Application Note: Couples an automotive SiC/IGBT traction inverter coolant loop with an e-compressor refrigerant chiller (R1234yf / R134a / R290) to evaluate coolant ΔT, junction temperature T_j, and chiller capacity margin.
▸ Governing Equations, Assumptions & Standards
1. Inverter Coolant Thermal Balance
T_in = T_out - [Q_inv · 1000] / [ρ · (V_dot / 60000) · (c_p · 1000)] | ΔT = T_out - T_in | ρ, c_p of the selected coolant (mass fractions) from CoolProp 8 at the mean coolant temperature (iterated)
2. Semiconductor Junction Temperature Network
T_j = T_out + Q_inv · R_th [°C; R_th = junction to coolant outlet temperature, includes baseplate, TIM and cold plate (conservative reference); T_j,max is an editable assumption]
3. E-Compressor Swept Volume & Refrigerant Flow
V_swept = (V_disp · N_rpm / 10^6) · 60 [m³/h] | m_dot_eff = η_vol · V_swept · ρ_ref [kg/h] | ρ_ref = ρ_v(T_e) · (T_e + 273.15) / (T_e + ΔT_sh + 273.15) (superheated vapour, ideal-gas scaling; or manual)
4. Chiller Evaporator Cooling Capacity
Q_evap = (m_dot_eff · Δh_net) / 3600 [kW] | Δh_net = h_g(T_e) + c_p,v(T_e) · ΔT_sh - h_f(T_liq) (CoolProp 8 saturation tables of the selected refrigerant; isenthalpic expansion, saturated-liquid enthalpy at T_liq) | Margin = Q_evap / Q_inv - 1 (< 0 = capacity deficit against the inverter loss only)
Plausibility: T_in must stay above the coolant freezing point → V_dot,min = Q_inv / [ρ · c_p · (T_out - T_freeze)]; notes are issued for T_in within 3 K of the freezing point and for T_in below T_e + 3 K (ALVC guide values).
Terminology context only, none of these documents is applied in the calculation: ISO 21498, IEC 60747-9, SAE J2765.
- Volumetric efficiency, superheat, liquid temperature and T_j,max are assumptions (defaults in the sidebar); the chiller capacity follows from the swept volume and the refrigerant state.
- Only the inverter loss is compared with the chiller capacity; the real chiller also serves other loads. R744 (transcritical) is not offered.
Brazed Radiator & Evaporator Core
Radiator Q_WT = 12.19 kW · Evaporator Q_VD = 6.67 kW (wet coil, SHR 0.56, 4.18 kg/h) · Core: 330 × 145.2 mm (4.79 dm²)
Radiator Heat Duty
12.19 kW (@ 80 K ITD)
Evaporator Cooling Duty
6.67 kW (1392 W/dm²)
Active Core Height
145.2 mm (4.79 dm²)
Frontal Air Speed
3.77 m/s (135.6 m³/h·dm²)
Sensible / Latent Split
3.71 / 2.97 kW · 4.18 kg/h
Core Cooling Capacity vs. Frontal Airflow
DIN EN 327 / 328 • ASHRAE Wet-Coil Psychrometrics
Application Note: Stacks brazed aluminum flat-tube (Flachrohr) and louvered-fin (Wellrippe) cores to evaluate specific frontal airflow loading v_L,norm, radiator heat rejection Q_WT, and wet/dry-coil evaporator duty Q_VD.
▸ Governing Equations, Assumptions & Standards
1. Core Geometry & Stacking Calculation
H_core = n_FR · h_FR + (n_FR + 1) · h_WR [mm] | A_dm2 = (B_core · H_core) / 10000 [dm²]
2. Specific Frontal Airflow Loading
v_L,norm = V_air / A_dm2 [m³/(h·dm²)] | v_L,eff = min(v_L,norm, v_L,max) | v_face = (V_air / 3600) / (A_dm2 / 100) [m/s]
3. Radiator Characteristic (WT, reference ITD = 80 K)
q80_norm = -0.0764 · v_L,eff² + 29.07 · v_L,eff + 6.6131 [W/dm²] | Q_WT = k_WT · (q80_norm · A_dm2 / 1000) · (ITD / 80) [kW] | the vertex of the q80 parabola is at v_L = 190.25, which is the upper limit of the characteristic (v_L,max)
4. Evaporator Characteristic (VD), scaled with the enthalpy potential
q0_norm = -0.0297 · v_L,eff² + 14.344 · v_L,eff - 6.6874 [W/dm²] (reference state: T_A1,ref, φ_ref, T_0,ref)
ε_ref = k_VD · (q0_norm · A_dm2 / 1000) / [ṁ_da,ref · Δh_max,ref] | Q_VD = ε_ref · ṁ_da · Δh_max · f_C [kW] | f_C = max(0.5, 1 - s_C · (T_C - 45))
Δh_max = h_1 - h_sat(T_0) (wet coil, T_0 < T_dew,1) or c_p,m · (T_A1 - T_0) (dry coil); the same expression is used for the actual and the reference state, so T_A1, φ_A1 and T_0 change Q_VD. s_C is an assumption without physical derivation (air-side coil duty does not depend on T_C).
5. Second-Law Air-Side Limits (ε_max, editable)
Q_WT ≤ ε_max · ṁ_air · c_p,air · ITD | Q_VD ≤ ε_max · ṁ_da · Δh_max
VD inlet state (T_A1, φ_A1) at p = 101.325 kPa (sea level, studio convention, no enhancement factor; W deviates from CoolProp HumidAir by up to −0.7 %): W_1 = 0.621945 · φ p_ws / (p - φ p_ws), h_1 = 1.006 t + W_1 (2501 + 1.86 t) [kJ/kg dry air], p_ws Hyland–Wexler (ASHRAE Fundamentals 2017 Ch. 1); ṁ_da = V̇_air / v_1
Outlet on the straight process line towards the saturated surface state (T_0, W_s(T_0)): β from h_2 = h_1 - Q / ṁ_da, T_2 = T_A1 - β(T_A1 - T_0), W_2 = W_1 - β(W_1 - W_s0) | Q_sens = ṁ_da (1.006 + 1.86 W_2)(T_A1 - T_2), Q_lat = Q_VD - Q_sens, condensate ṁ_w = ṁ_da (W_1 - W_2)
Terminology context only, none of these documents is applied in the calculation: DIN EN 327, DIN EN 328, VDI Heat Atlas Chapter M.
- Brazed aluminum core with flat-tube thickness h_FR and corrugated louvered fin height h_WR; the reference polynomials come from an undocumented block, therefore k_WT, k_VD, v_L,max and the VD reference state are editable assumptions.
- Frost formation (T_0 ≤ 0 °C), coolant-side limits and fin efficiency are not modelled.
Finned-Tube Coil Simulator
CONDENSER Duty Q_coil = 4.14 kW · Fluid: R134a · Air: 1800 m³/h · Area: 18.2 m²
Total Coil Capacity
4.14 kW
Outlet Air Temperature
39.1 °C
External Finned Area
18.2 m²
Refrigerant Pressure Drop
2.39 kPa
Heat Transfer Breakdown
—
Coil Temperature Profile & Phase Zones
Shah (2009) • Gungor-Winterton (1987) • Gray-Webb (1986)
Application Note: Moving-boundary multi-circuit round-tube finned-coil solver (condenser, wet/dry evaporator, and R744 supercritical gas cooler) using Gray & Webb air-side j-factor, Shah / Gungor–Winterton two-phase h_ref, and Müller-Steinhagen & Heck Δp.
▸ Governing Equations, Assumptions & Standards
1. Overall Conductance (air + wall + refrigerant side)
UA = 1 / [ 1/(η_o · h_air · A_ext) + R_wall + 1/(h_ref · A_i) ] | R_wall = ln(D_o/D_i) / (2π k_Cu L_tot), smooth Cu tube, wall 0.35 mm, k = 390 W/mK | A_i = π D_i L_tot | two-phase zones: UA averaged over the zone's quality range (uniform heat flux → x linear along the tube)
Condensation: Shah (2009), HVAC&R Res. 15:889 — h_LS = 0.023 Re_LS^0.8 Pr_L^0.4 k_L/D_i (Re_LS = G(1-x)D_i/μ_L), Z = (1/x - 1)^0.8 p_r^0.4, h_I = h_LS (μ_L/14μ_G)^(0.0058+0.557 p_r) (1 + 3.8/Z^0.95), h_Nu = 1.32 Re_LS^(-1/3) [ρ_L(ρ_L-ρ_G) g k_L³/μ_L²]^(1/3); horizontal: J_g = xG/[gDρ_G(ρ_L-ρ_G)]^0.5 ≥ 0.98(Z+0.263)^-0.62 → h = h_I, otherwise h = h_I + h_Nu
Evaporation: Gungor & Winterton (1987), Chem. Eng. Res. Des. 65:148 — h = E · h_L, E = 1 + 3000 Bo^0.86 + 1.12 (x/(1-x))^0.75 (ρ_L/ρ_G)^0.41, Bo = q/(G h_fg) (iterated with the zone heat flux), horizontal tube with Fr_L < 0.05: E · Fr_L^(0.1-2Fr_L) | single phase (vapour, liquid, supercritical CO2): Gnielinski (Petukhov f), Nu = 3.66 laminar, blend 2300–4000
2. Zone Model (moving boundary, every zone sees fresh inlet air)
Condenser: inlet vapour T_sat + ΔT_sh,in → desuperheat zone (crossflow ε-NTU, air unmixed / refrigerant mixed) → two-phase zone Q = η_maldist · f · C_air (1 - e^(-UA/C_air)) (T_sat - T_air,in) → subcool zone with the remaining area; subcooling (or outlet quality x_out) is a result. h_fg, c_p, ρ, μ, k from CoolProp 8 at T_sat (SatTables; vapour μ/k and superheat enthalpy: coil_ref_props.js)
Evaporator: inlet quality from isenthalpic expansion x_in = [h_L(T_liq) - h_L(T_sat)] / h_fg(T_sat) (subcooled liquid h ≈ h_L(T); R744 with T_liq > T_c: h(p_high, T_liq) of the gas-cooler outlet) → two-phase zone x_in → 1 → superheat zone; superheat (or x_out < 1) is a result
Wet coil (evaporator, T_dew,in > T_sat): enthalpy-potential ε-NTU (Threlkeld; Braun, Klein & Mitchell 1989): UA* = 1/[c_p,m/(η_o,w h_air A_ext) + c_s (R_wall + 1/(h_ref A_i))], Q = η_maldist ṁ_da (1 - e^(-UA*/ṁ_da)) (h_air,in - h_sat(T_sat)), c_s = dh_sat/dT between T_sat and the mean wet-surface temperature, wet fin efficiency with m_w = m √(c_s/c_p,m); the larger of the completely dry and completely wet duty is used; outlet humidity via the effective-surface state; condensate = ṁ_da (W_in - W_out)
R744 above T_c (condenser mode): gas cooler at p_high, refrigerant path split into 40 segments (each 1/40 of area and air flow, crossflow ε-NTU), CO2 h, c_p, μ, k from a CoolProp table at 75–140 bar, marching in enthalpy (exact energy balance); N = 40 is within 0.2 % of N = 400
3. Extended Surface & Air-Side Conductance
A_tube = π D_o (L - n_fins t_fin) N_tubes | A_fins = 2 n_fins [H_face Depth - N_tubes π D_c²/4] (tube holes deducted, D_c = D_o + 2 t_fin) | A_ext = A_tube + A_fins | H_face = tubes · P_t, Depth = rows · P_l
Fin efficiency, Schmidt (1949) sector method, staggered tubes: X_M = P_t/2, X_L = ½ √[(P_t/2)² + P_l²], r_e/r = 1.27 (X_M/r) √(X_L/X_M - 0.3), φ = (r_e/r - 1)(1 + 0.35 ln(r_e/r)), η_f = tanh(m r φ)/(m r φ), m = √(2 h_air / (k_fin t_fin)); η_o = 1 - (A_fins/A_ext)(1 - η_f); fin-collar contact resistance neglected
Plain fin, staggered round tubes (Gray & Webb 1986, coefficients as given in Webb & Kim 2005): j4 = 0.14 · ReDc-0.328 · (Pt/Pl)-0.502 · (s/Dc)0.0312 (N ≥ 4 rows), jN/j4 = 0.991 · [2.24 · ReDc-0.092 · (N/4)-0.031]0.607 (4-N) (N < 4: the data base of the correlation is N ≥ 4, the row correction extrapolates); ReDc on the minimum free-flow area, valid for ReDc 500 – 25 000 (a note is issued outside); h_air = j · G · c_p / Pr^(2/3), μ_air, k_air (Sutherland, White) and Pr at the air inlet temperature | air inlet state (T_air,in, φ_in) at 101.325 kPa: ASHRAE Fundamentals 2017 psychrometrics, ṁ_da = V̇/v
4. Refrigerant Pressure Drop & Air Velocity Maldistribution
Straight-tube friction per zone, integrated over the zone path length (zone area fraction × circuit length; circuit length = rows · tubes / circuits · L): single phase dp/dz = f/D_i · G²/(2ρ), f = 64/Re (Re < 2000), Haaland smooth-tube f above Re 3000 (blend in between); two phase, Müller-Steinhagen & Heck (1986): (dp/dz) = [A + 2(B - A)x](1 - x)^(1/3) + B x³, A / B = liquid-only / vapour-only gradient at the full mass flux, averaged over the zone's quality range. Return bends, headers, momentum and gravity terms and the T_sat change along the circuit are not included (the result is a lower bound of the real pressure drop). | η_maldist = max(0.65, 1.0 - 0.45 · σ_air²) (assumed form, multiplies every zone duty)
Rating context only, not applied: AHRI Standard 410 • ASHRAE Standard 33 (not a certified rating calculation) • properties: CoolProp 8.0 (HEOS); R1233zd(E) vapour μ/k estimated (corresponding states / Perkins & Huber 2017) • air-side j: Gray & Webb (1986), Proc. 8th Int. Heat Transfer Conf., cross-checked against McQuiston (1978), ASHRAE Trans. 84(1).
- Staggered tube bundle; tube pitches, fin thickness and fin conductivity are editable assumptions (defaults 25.4 mm / 22.0 mm / 0.11 mm / 200 W/mK); smooth (not micro-fin) copper tubes, wall 0.35 mm, k = 390 W/mK; fin-collar contact resistance neglected.
- Refrigerant distribution is evenly split across parallel circuits; zones see fresh inlet air (row-by-row air heating/cooling of a multi-row counter-crossflow coil not resolved); the maldistribution factor is an assumed form.
- Mode switch loads the air-inlet defaults 32 °C / 40 % (condenser) or 27 °C / 47 % (evaporator, = 27 °C DB / 19 °C WB) and T_sat 45 / 5 °C. Superheat zone of the evaporator treated as dry; frost not modelled.
- R744: T_sat only selects subcritical operation (T_sat < 30.98 °C) or the gas cooler (T_sat ≥ T_c, then p_high and T_gc,in apply); the gas-cooler Nusselt number (Gnielinski at bulk properties) has no property-variation correction near the pseudo-critical temperature; evaporator liquid enthalpy always from (p_high, T_liq).
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ISO 10303 STEP AP214/AP242 + Native CAD & ISO GPS Drawing Export |
Zero-Cloud Privacy: Neutral 3D B-Rep files are processed directly in your browser session; translated files run in volatile RAM and are never stored.
Application Note: 3D B-Rep/mesh & 2D drawing workstation with X/Y/Z clipping planes, 3D snap caliper, and DIN ISO 128-50 / ISO GPS section sheet.
ADVANCED MODE • PRO PREVIEW
2D ISO Technical Drawing Studio & 3D DFM Analyzer
Locked Enterprise Partner / Pro Feature: Configure full ISO 5457 / ISO 128 multi-view drawings (A0–A4) and automated manufacturing rules below. Production export & CAD release sign-off require an authorized Enterprise Partner key.
1 · Sheet Format & Projection (ISO 5457 / ISO 5456-2)
2 · Standard Views (ISO 128-30 / ISO 128-50 / ISO 5456-3)
3 · Manufacturing Process & Material Rules
4 · Editable Title Block (DIN EN ISO 7200)
LIVE ISO MULTI-VIEW SHEET PREVIEW (FRONT + TOP + SIDE + SECTION A–A + ISOMETRIC)
PDF/DXF Release Locked (PRO)
Applied Standards: ISO 5457 (Drawing sheet layout & grid zones) • ISO 128-30/40/50 (Orthographic & section views) • ISO 5456-2/3 (First/Third-angle & isometric axonometry) • ISO 129-1 (Dimensioning) • ISO 1101 / ISO 5459 (Geometrical tolerances & datums) • ISO 21920 (Surface texture) • ISO 2768-mK / EN 12020-2 • DIN EN ISO 7200 (Title block).
01 · 3D Wall-Thickness & Fin Aspect DFM
Automated raycast wall-thickness map (tmin check for HPDC / CNC / Extrusion), fin aspect ratio (Hfin/s) tool-deflection check, and minimum internal corner radius (R ≥ 1.5 mm) verification.
02 · Multi-Point CMM Inspection Table
Persistent 3D coordinate metrology list: store multiple Point-to-Point, Parallel-Plane (d⊥), Bore Center-to-Center, and Flatness datum measurements with CSV/PDF CMM report export.
03 · CNC Tool Access & Thread Port Audit
3-axis / 5-axis spindle accessibility shading, undercut detection, O-ring groove & G1/4" / G3/8" port edge-distance check, and EU TARIC / US HTS customs mass breakdown.