Hvac Psychrometrics

{
  "elevation": 0,
  "inputs_used": {
    "dry_bulb": 95,
    "wet_bulb": 75
  },
  "next_calls": [
    {
      "arguments": {
        "airflow": 1000,
        "entering": {
          "dry_bulb": 95,
          "wet_bulb": 75
        },
        "leaving": {
          "dry_bulb": 55,
          "wet_bulb": 54
        },
        "units": "IP"
      },
      "price": "$0.002",
      "tool": "hvac_coil_load",
      "why": "What load does a coil carry cooling this air to 55/54 °F at 1000 CFM?"
    }
  ],
  "notes": [],
  "pressure": 14.696,
  "references": [
    "ASHRAE Handbook—Fundamentals (2021), Ch. 1 Psychrometrics"
  ],
  "state": {
    "density": 0.07092,
    "dew_point": 66.76,
    "dry_bulb": 95,
    "enthalpy": 38.316,
    "grains": 98.46,
    "humidity_ratio": 0.014065,
    "relative_humidity": 39.82,
    "specific_volume": 14.2995,
    "vapor_pressure": 0.325,
    "wet_bulb": 75
  },
  "steps": [
    {
      "calculation": "p = 14.696 × (1 − 6.8754×10⁻⁶ × Z)^5.2559 = 14.696 × (1 − 6.8754×10⁻⁶ × 0)^5.2559 = 14.6960 psia",
      "reference": "ASHRAE Handbook—Fundamentals (2021), Ch. 1 Psychrometrics, Eq. 3",
      "step": "Atmospheric pressure"
    },
    {
      "calculation": "pws(75.00 °F wet bulb) = 0.43007 psia (ASHRAE Ch. 1 Eq. 6)",
      "reference": "ASHRAE Handbook—Fundamentals (2021), Ch. 1 Psychrometrics",
      "step": "Humidity ratio"
    },
    {
      "calculation": "Ws* = 0.621945 × pws / (p − pws) = 0.018750 lb/lb (saturated at the wet bulb)",
      "reference": "ASHRAE Handbook—Fundamentals (2021), Ch. 1 Psychrometrics",
      "step": "Humidity ratio"
    }
  ],
  "unit_labels": {
    "airflow": "CFM",
    "area": "ft²",
    "condensate": "gal / h",
    "density": "lb / ft³",
    "elevation": "ft",
    "enthalpy": "BTU / lb dry air",
    "friction_rate": "in. w.g. / 100 ft",
    "grains": "gr / lb dry air",
    "humidity_ratio": "lb water / lb dry air",
    "length": "in",
    "load": "MBH (1,000 BTU/h)",
    "pressure": "psia",
    "relative_humidity": "%",
    "specific_volume": "ft³ / lb dry air",
    "temperature": "°F",
    "velocity": "FPM",
    "velocity_pressure": "in. w.g."
  },
  "units": "IP"
}

# bash or zsh: see the payment challenge. Nothing is charged.
curl -sS -g -i -X POST 'https://x402-agent-api.onrender.com/api/v1/hvac-psychrometrics' \
  -H 'content-type: application/json' \
  --data-raw '{"dry_bulb":95,"elevation":0,"wet_bulb":75}'

# x402 v2 sends the challenge base64-encoded in the PAYMENT-REQUIRED header (v1 sends it in the body).
# To read the header:
curl -sS -g -o /dev/null -D - -X POST 'https://x402-agent-api.onrender.com/api/v1/hvac-psychrometrics' \
  -H 'content-type: application/json' \
  --data-raw '{"dry_bulb":95,"elevation":0,"wet_bulb":75}' \
  | grep -i '^payment-required:' | cut -d' ' -f2 | tr -d '\r' | base64 --decode

// npm i @x402/fetch @x402/evm viem
import { wrapFetchWithPayment, x402Client } from "@x402/fetch";
import { registerExactEvmScheme } from "@x402/evm/exact/client";
import { privateKeyToAccount } from "viem/accounts";

// Pays at most $0.002 per call.
const client = new x402Client().setSpendControls({ maxAmountPerPayment: "$0.002" });
registerExactEvmScheme(client, { signer: privateKeyToAccount(process.env.EVM_PRIVATE_KEY) });
const pay = wrapFetchWithPayment(fetch, client);

// Not sure it's safe to pay? ToolVet checks it first for $0.005. Pay for that from a separate
// client: this one is capped at $0.002 per payment. GET https://toolvet.app/api/v1/check?url=https%3A%2F%2Fx402-agent-api.onrender.com%2Fapi%2Fv1%2Fhvac-psychrometrics&method=POST
const res = await pay("https://x402-agent-api.onrender.com/api/v1/hvac-psychrometrics", {
  method: "POST",
  headers: { "content-type": "application/json" },
  body: JSON.stringify({
    "dry_bulb": 95,
    "elevation": 0,
    "wet_bulb": 75
  }),
});
console.log(res.status, await res.text());

# pip install "x402[requests,evm]"
import os
from eth_account import Account
from x402 import x402ClientSync
from x402.http.clients import x402_requests
from x402.mechanisms.evm import EthAccountSigner
from x402.mechanisms.evm.exact.register import register_exact_evm_client

# Pays at most $0.002 per call.
client = x402ClientSync().set_spend_controls({"max_amount_per_payment": "$0.002"})
register_exact_evm_client(client, EthAccountSigner(Account.from_key(os.environ["EVM_PRIVATE_KEY"])))

with x402_requests(client) as session:
    res = session.post(
        "https://x402-agent-api.onrender.com/api/v1/hvac-psychrometrics",
        json={
            "dry_bulb": 95,
            "elevation": 0,
            "wet_bulb": 75,
        },
    )
    print(res.status_code, res.text)